A115744 Triangular numbers that are the product of 2 palindromes greater than 1.
6, 10, 15, 21, 28, 36, 45, 55, 66, 231, 528, 666, 1128, 2016, 2211, 2628, 2775, 3003, 3570, 3916, 4095, 5995, 6105, 6216, 6903, 8646, 21736, 31878, 34980, 37950, 43956, 45753, 52003, 58653, 65703, 66066, 73153, 83028, 89676, 93528, 116886
Offset: 1
Examples
6903=T(117) and 6903=9*767.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..83 (All terms less than 1 million)
Programs
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Mathematica
Module[{upto=120000,pals},pals=Select[Range[2,upto/2],PalindromeQ];Select[ Times@@@Tuples[pals,2],OddQ[Sqrt[8#+1]]&&#<=upto&]]//Union (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 13 2018 *)