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 A066702 #20 Apr 13 2019 22:12:57
%S A066702 0,1,1306449,1044000721,12957041241,1019072079081,1174279984164,
%T A066702 6454272356676,65036563475625,67624587155889,123826990849454025,
%U A066702 170448128872993657764,19198191503444720114404
%N A066702 Square numbers whose reverse is triangular with the same number of digits.
%C A066702 The sequence of corresponding triangular numbers is A066703. - _Robert G. Wilson v_, Jan 31 2011
%e A066702 9446031 is triangular and 1306449 is a square.
%t A066702 lst = {0}; For[i = 1, i > 0, i++, s = i^2; t = FromDigits@ Reverse@ IntegerDigits@ s; If[ IntegerQ@ Sqrt[8 t + 1] && Mod[s, 10] > 0, AppendTo[lst, s]; Print@ lst]]
%Y A066702 Cf. A066703, A181412. - _Harvey P. Dale_, Jan 30 2011
%K A066702 base,more,nonn
%O A066702 1,3
%A A066702 _Erich Friedman_, Jan 14 2002
%E A066702 a(12)-a(13) from and offset corrected by _Giovanni Resta_, Jun 20 2015