1921/1/1: 010121 = 010:121 = each is palindrome
1921/1/2: 020121 = 020:121 = each is palindrome
1921/1/2: 1221 = palindrome
1921/1/2: 21012 = palindrome
1921/1/2: 2112 = palindrome
1921/1/2: 2121 = cyclic permutation symmetric
1921/1/3: 030121 = 030:121 = each is palindrome
1921/1/4: 040121 = 040:121 = each is palindrome
1921/1/5: 050121 = 050:121 = each is palindrome
1921/1/5: 210105 = 210:105 = integer ratio of 2 to 1
1921/1/6: 060121 = 060:121 = each is palindrome
1921/1/7: 070121 = 070:121 = each is palindrome
1921/1/7: 171921 = 17:19:21 = arthimetic series of increment 2
1921/1/8: 080121 = 080:121 = each is palindrome
1921/1/9: 090121 = 090:121 = each is palindrome
1921/1/11: 011121 = 01:11:21 = arthimetic series of increment 10
1921/1/11: 011121 = 011:121 = integer ratio of 1 to 11
1921/1/12: 12121 = palindrome
1921/1/12: 21112 = palindrome
1921/1/13: 01131921 = 0113:1921 = integer ratio of 1 to 17
1921/1/13: 19210113 = 1921:0113 = integer ratio of 17 to 1
1921/1/20: 12021 = palindrome
1921/1/21: 12121 = palindrome
1921/1/22: 12221 = palindrome
1921/1/23: 12321 = palindrome
1921/1/24: 12421 = palindrome
1921/1/25: 12521 = palindrome
1921/1/26: 12621 = palindrome
1921/1/27: 12721 = palindrome
1921/1/28: 12821 = palindrome
1921/1/29: 1291921 = palindrome
1921/1/29: 12921 = palindrome
1921/2/1: 020121 = 020:121 = each is palindrome
1921/2/1: 1221 = palindrome
1921/2/1: 2121 = cyclic permutation symmetric
1921/2/3: 192123 = 19:21:23 = arthimetic series of increment 2
1921/2/4: 4221 = 42:21 = integer ratio of 2 to 1
1921/2/9: 921921 = cyclic permutation symmetric
1921/2/10: 021021 = cyclic permutation symmetric
1921/2/10: 210210 = cyclic permutation symmetric
1921/2/12: 12221 = palindrome
1921/2/12: 21212 = palindrome
1921/3/1: 030121 = 030:121 = each is palindrome
1921/3/4: 4321 = 4:3:2:1 = arthimetic series of increment -1
1921/3/6: 6321 = 63:21 = integer ratio of 3 to 1
1921/3/12: 031221 = 03:12:21 = arthimetic series of increment 9
1921/3/12: 12321 = palindrome
1921/3/12: 21312 = palindrome
1921/4/1: 040121 = 040:121 = each is palindrome
1921/4/2: 2142 = 21:42 = integer ratio of 1 to 2
1921/4/2: 4221 = 42:21 = integer ratio of 2 to 1
1921/4/3: 4321 = 4:3:2:1 = arthimetic series of increment -1
1921/4/8: 8421 = 8:4:2:1 = geometric series of ratio 0.5
1921/4/8: 8421 = 84:21 = integer ratio of 4 to 1
1921/4/12: 12421 = palindrome
1921/4/12: 21412 = palindrome
1921/4/20: 042021 = 042:021 = integer ratio of 2 to 1
1921/4/20: 210420 = 210:420 = integer ratio of 1 to 2
1921/5/1: 050121 = 050:121 = each is palindrome
1921/5/12: 12521 = palindrome
1921/5/12: 21512 = palindrome
1921/5/13: 051321 = 05:13:21 = arthimetic series of increment 8
1921/6/1: 060121 = 060:121 = each is palindrome
1921/6/3: 2163 = 21:63 = integer ratio of 1 to 3
1921/6/3: 6321 = 63:21 = integer ratio of 3 to 1
1921/6/12: 12621 = palindrome
1921/6/12: 21612 = palindrome
1921/6/30: 063021 = 063:021 = integer ratio of 3 to 1
1921/6/30: 210630 = 210:630 = integer ratio of 1 to 3
1921/7/1: 070121 = 070:121 = each is palindrome
1921/7/1: 171921 = 17:19:21 = arthimetic series of increment 2
1921/7/12: 12721 = palindrome
1921/7/12: 21712 = palindrome
1921/7/14: 071421 = 07:14:21 = arthimetic series of increment 7
1921/8/1: 080121 = 080:121 = each is palindrome
1921/8/4: 2184 = 21:84 = integer ratio of 1 to 4
1921/8/4: 8421 = 8:4:2:1 = geometric series of ratio 0.5
1921/8/4: 8421 = 84:21 = integer ratio of 4 to 1
1921/8/12: 12821 = palindrome
1921/8/12: 21812 = palindrome
1921/9/1: 090121 = 090:121 = each is palindrome
1921/9/2: 192192 = cyclic permutation symmetric
1921/9/2: 921921 = cyclic permutation symmetric
1921/9/12: 1291921 = palindrome
1921/9/12: 12921 = palindrome
1921/9/12: 21912 = palindrome
1921/9/15: 091521 = 09:15:21 = arthimetic series of increment 6
1921/10/1: 211001 = 211:001 = integer ratio of 211 to 1
1921/10/2: 021021 = cyclic permutation symmetric
1921/10/11: 101121 = 101:121 = each is palindrome
1921/10/23: 231021 = 231:021 = integer ratio of 11 to 1
1921/11/1: 011121 = 01:11:21 = arthimetic series of increment 10
1921/11/1: 011121 = 011:121 = integer ratio of 1 to 11
1921/11/1: 211101 = 21:11:01 = arthimetic series of increment -10
1921/11/2: 21112 = palindrome
1921/11/10: 101121 = 101:121 = each is palindrome
1921/11/11: 111121 = 111:121 = each is palindrome
1921/11/12: 121121 = palindrome
1921/11/12: 121121 = cyclic permutation symmetric
1921/11/12: 121121 = 121:121 = each is palindrome
1921/11/12: 211112 = palindrome
1921/11/13: 131121 = 131:121 = each is palindrome
1921/11/14: 141121 = 141:121 = each is palindrome
1921/11/15: 151121 = 151:121 = each is palindrome
1921/11/16: 111621 = 11:16:21 = arthimetic series of increment 5
1921/11/16: 161121 = 161:121 = each is palindrome
1921/11/17: 171121 = 171:121 = each is palindrome
1921/11/18: 181121 = 181:121 = each is palindrome
1921/11/19: 191121 = 191:121 = each is palindrome
1921/12/1: 12121 = palindrome
1921/12/2: 12221 = palindrome
1921/12/3: 031221 = 03:12:21 = arthimetic series of increment 9
1921/12/3: 12321 = palindrome
1921/12/3: 211203 = 21:12:03 = arthimetic series of increment -9
1921/12/4: 12421 = palindrome
1921/12/5: 12521 = palindrome
1921/12/6: 12621 = palindrome
1921/12/7: 12721 = palindrome
1921/12/8: 12821 = palindrome
1921/12/9: 1291921 = palindrome
1921/12/9: 12921 = palindrome
1921/12/11: 121121 = palindrome
1921/12/11: 121121 = cyclic permutation symmetric
1921/12/11: 121121 = 121:121 = each is palindrome
1921/12/11: 211211 = cyclic permutation symmetric
1921/12/22: 122221 = palindrome
1921/12/22: 221221 = cyclic permutation symmetric