A066528 Non-palindromic triangular numbers whose reverse is a triangular number with the same number of digits.

153, 351, 17578, 87571, 185745, 547581, 1461195, 5911641, 12145056, 12517506, 60571521, 65054121, 304119453, 354911403, 1775275491, 1945725771, 10246462281, 17990863516, 18226464201, 35615002605, 50620051653, 61536809971, 1222080857271, 1664224065406

Offset: 1

Author

Erich Friedman, Jan 08 2002

Keywords

• base
• nonn

Examples

			153 and 351 are both triangular.
		

Links

• Giovanni Resta, Table of n, a(n) for n = 1..64 (terms < 2*10^24)

Crossrefs

See A069673 for another version.

Cf. A066703, A179889.

Cf. A003098, A061455, A066569, A069673.

Programs

Mathematica

dtn[L_] := Fold[10#1+#2&, 0, L]; tritest[n_] := Module[{t}, t=Floor[N[Sqrt[2n]]]; 2n==t(t+1)]; A={}; For[i=1, i>0, i++, t=i(i+1)/2; If[tritest[tt=dtn[Reverse[IntegerDigits[t]]]]&&Mod[t, 10]>0&&t=!=tt, AppendTo[A, t]; Print[A]]]

Extensions

a(22)-a(24) from Giovanni Resta, Jun 20 2015