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

1,1

Links

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

Example

153 and 351 are both triangular.

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]]]

Crossrefs

See A069673 for another version.

Cf. A066703, A179889.

Cf. A003098, A061455, A066569, A069673.

Sequence in context: A159294 A332228 A349755 * A046197 A271730 A056733

Adjacent sequences: A066525 A066526 A066527 * A066529 A066530 A066531

Keyword

base,nonn

Author

Erich Friedman, Jan 08 2002

Extensions

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

Status

approved