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

Author

Giovanni Resta, Jan 31 2006

Keywords

• nonn
• base

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)

Crossrefs

Cf. A115683, A115743, A115745.

Programs

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 *)