This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A066741 #23 May 19 2025 08:16:29
%S A066741 0,1,925,1426,6112,9801,140301,52244922262,1445531162626,
%T A066741 5205252778462,63253297234426,9040940929621480310251
%N A066741 Pentagonal numbers not divisible by 10 whose reverse is a square.
%C A066741 a(13) > 2^63. - _Donovan Johnson_, May 24 2011
%e A066741 925 is pentagonal and 529 is square.
%t A066741 dtn[L_] := Fold[10#1+#2&, 0, L] A={0}; For[i=1, i>0, i++, t=i(3i-1)/2; r=dtn[Reverse[IntegerDigits[t]]]; If[IntegerQ[Sqrt[r]]&&Mod[t, 10]>0, AppendTo[A, t]; Print[A]]]
%Y A066741 Cf. A000290, A000326, A067251.
%K A066741 base,more,nonn
%O A066741 1,3
%A A066741 _Erich Friedman_, Jan 16 2002
%E A066741 a(12) from _Donovan Johnson_, Apr 03 2008
%E A066741 Offset corrected by _Donovan Johnson_, May 24 2011
%E A066741 Description clarified and a(12) corrected by _Lars Blomberg_, May 29 2011