1999/1/1: 111999 = 111:999 = integer ratio of 1 to 9 1999/1/1: 111999 = 111:999 = each is single digit 1999/1/1: 111999 = 111:999 = each is palindrome 1999/1/1: 111999 = 111:999 = each is cyclic permutation symmetric 1999/1/1: 1199 = 11:99 = integer ratio of 1 to 9 1999/1/1: 1199 = 11:99 = each is single digit 1999/1/1: 1199 = 11:99 = each is palindrome 1999/1/1: 1199 = 11:99 = each is cyclic permutation symmetric 1999/1/1: 9911 = 99:11 = integer ratio of 9 to 1 1999/1/1: 9911 = 99:11 = each is single digit 1999/1/1: 9911 = 99:11 = each is palindrome 1999/1/1: 9911 = 99:11 = each is cyclic permutation symmetric 1999/1/2: 121999 = 121:999 = each is palindrome 1999/1/3: 131999 = 131:999 = each is palindrome 1999/1/4: 141999 = 141:999 = each is palindrome 1999/1/5: 151999 = 151:999 = each is palindrome 1999/1/6: 161999 = 161:999 = each is palindrome 1999/1/7: 171999 = 171:999 = each is palindrome 1999/1/8: 181999 = 181:999 = each is palindrome 1999/1/9: 010999 = 010:999 = each is palindrome 1999/1/9: 191999 = 191:999 = each is palindrome 1999/1/10: 011099 = 011:099 = integer ratio of 1 to 9 1999/1/10: 990110 = 990:110 = integer ratio of 9 to 1 1999/2/1: 121999 = 121:999 = each is palindrome 1999/2/2: 2299 = 22:99 = each is single digit 1999/2/2: 2299 = 22:99 = each is palindrome 1999/2/2: 2299 = 22:99 = each is cyclic permutation symmetric 1999/2/2: 9922 = 99:22 = each is single digit 1999/2/2: 9922 = 99:22 = each is palindrome 1999/2/2: 9922 = 99:22 = each is cyclic permutation symmetric 1999/2/9: 020999 = 020:999 = each is palindrome 1999/2/13: 021399 = 021:399 = integer ratio of 1 to 19 1999/3/1: 131999 = 131:999 = each is palindrome 1999/3/3: 3399 = 33:99 = integer ratio of 1 to 3 1999/3/3: 3399 = 33:99 = each is single digit 1999/3/3: 3399 = 33:99 = each is palindrome 1999/3/3: 3399 = 33:99 = each is cyclic permutation symmetric 1999/3/3: 9933 = 99:33 = integer ratio of 3 to 1 1999/3/3: 9933 = 99:33 = each is single digit 1999/3/3: 9933 = 99:33 = each is palindrome 1999/3/3: 9933 = 99:33 = each is cyclic permutation symmetric 1999/3/9: 030999 = 030:999 = each is palindrome 1999/3/18: 031899 = 031:899 = integer ratio of 1 to 29 1999/3/30: 033099 = 033:099 = integer ratio of 1 to 3 1999/3/30: 990330 = 990:330 = integer ratio of 3 to 1 1999/4/1: 141999 = 141:999 = each is palindrome 1999/4/4: 4499 = 44:99 = each is single digit 1999/4/4: 4499 = 44:99 = each is palindrome 1999/4/4: 4499 = 44:99 = each is cyclic permutation symmetric 1999/4/4: 9944 = 99:44 = each is single digit 1999/4/4: 9944 = 99:44 = each is palindrome 1999/4/4: 9944 = 99:44 = each is cyclic permutation symmetric 1999/4/9: 040999 = 040:999 = each is palindrome 1999/5/1: 151999 = 151:999 = each is palindrome 1999/5/5: 5599 = 55:99 = each is single digit 1999/5/5: 5599 = 55:99 = each is palindrome 1999/5/5: 5599 = 55:99 = each is cyclic permutation symmetric 1999/5/5: 9955 = 99:55 = each is single digit 1999/5/5: 9955 = 99:55 = each is palindrome 1999/5/5: 9955 = 99:55 = each is cyclic permutation symmetric 1999/5/9: 050999 = 050:999 = each is palindrome 1999/6/1: 161999 = 161:999 = each is palindrome 1999/6/6: 6699 = 180 deg rotationally symmetric 1999/6/6: 6699 = 66:99 = each is single digit 1999/6/6: 6699 = 66:99 = each is palindrome 1999/6/6: 6699 = 66:99 = each is cyclic permutation symmetric 1999/6/6: 99066 = 180 deg rotationally symmetric 1999/6/6: 9966 = 180 deg rotationally symmetric 1999/6/6: 9966 = 99:66 = each is single digit 1999/6/6: 9966 = 99:66 = each is palindrome 1999/6/6: 9966 = 99:66 = each is cyclic permutation symmetric 1999/6/9: 060999 = 060:999 = each is palindrome 1999/7/1: 171999 = 171:999 = each is palindrome 1999/7/7: 7799 = 77:99 = each is single digit 1999/7/7: 7799 = 77:99 = each is palindrome 1999/7/7: 7799 = 77:99 = each is cyclic permutation symmetric 1999/7/7: 9977 = 99:77 = each is single digit 1999/7/7: 9977 = 99:77 = each is palindrome 1999/7/7: 9977 = 99:77 = each is cyclic permutation symmetric 1999/7/9: 070999 = 070:999 = each is palindrome 1999/8/1: 181999 = 181:999 = each is palindrome 1999/8/8: 8899 = 88:99 = each is single digit 1999/8/8: 8899 = 88:99 = each is palindrome 1999/8/8: 8899 = 88:99 = each is cyclic permutation symmetric 1999/8/8: 9988 = 99:88 = each is single digit 1999/8/8: 9988 = 99:88 = each is palindrome 1999/8/8: 9988 = 99:88 = each is cyclic permutation symmetric 1999/8/9: 080999 = 080:999 = each is palindrome 1999/9/1: 010999 = 010:999 = each is palindrome 1999/9/1: 191999 = 191:999 = each is palindrome 1999/9/1: 199991 = palindrome 1999/9/2: 020999 = 020:999 = each is palindrome 1999/9/3: 030999 = 030:999 = each is palindrome 1999/9/4: 040999 = 040:999 = each is palindrome 1999/9/5: 050999 = 050:999 = each is palindrome 1999/9/5: 199995 = 199:995 = integer ratio of 1 to 5 1999/9/6: 060999 = 060:999 = each is palindrome 1999/9/7: 070999 = 070:999 = each is palindrome 1999/9/8: 080999 = 080:999 = each is palindrome 1999/9/9: 090999 = 090:999 = each is palindrome 1999/9/9: 99099 = palindrome 1999/9/9: 9999 = single digit 1999/9/9: 9999 = palindrome 1999/9/9: 9999 = cyclic permutation symmetric 1999/9/9: 9999 = 99:99 = each is single digit 1999/9/9: 9999 = 99:99 = each is palindrome 1999/9/9: 9999 = 99:99 = each is cyclic permutation symmetric 1999/10/1: 011099 = 011:099 = integer ratio of 1 to 9 1999/10/1: 991001 = 991:001 = integer ratio of 991 to 1 1999/10/19: 101999 = 101:999 = each is palindrome 1999/11/11: 111199 = 11:11:99 = each is single digit 1999/11/11: 111199 = 11:11:99 = each is palindrome 1999/11/11: 111199 = 11:11:99 = each is cyclic permutation symmetric 1999/11/11: 991111 = 99:11:11 = each is single digit 1999/11/11: 991111 = 99:11:11 = each is palindrome 1999/11/11: 991111 = 99:11:11 = each is cyclic permutation symmetric 1999/11/19: 111999 = 111:999 = integer ratio of 1 to 9 1999/11/19: 111999 = 111:999 = each is single digit 1999/11/19: 111999 = 111:999 = each is palindrome 1999/11/19: 111999 = 111:999 = each is cyclic permutation symmetric 1999/11/22: 112299 = 11:22:99 = each is single digit 1999/11/22: 112299 = 11:22:99 = each is palindrome 1999/11/22: 112299 = 11:22:99 = each is cyclic permutation symmetric 1999/11/22: 221199 = 22:11:99 = each is single digit 1999/11/22: 221199 = 22:11:99 = each is palindrome 1999/11/22: 221199 = 22:11:99 = each is cyclic permutation symmetric 1999/11/22: 991122 = 99:11:22 = each is single digit 1999/11/22: 991122 = 99:11:22 = each is palindrome 1999/11/22: 991122 = 99:11:22 = each is cyclic permutation symmetric 1999/12/19: 121999 = 121:999 = each is palindrome