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 A181412 #35 Jun 21 2015 14:14:16 %S A181412 1,100,10000,1000000,1306449,100000000,130644900,1044000721, %T A181412 10000000000,12957041241,13064490000,104400072100,1000000000000, %U A181412 1019072079081,1174279984164,1295704124100,1306449000000,6454272356676,10440007210000 %N A181412 Squares whose reverse is a triangular number; trailing zeros are permitted. %C A181412 Suggested by _T. D. Noe_. %H A181412 Giovanni Resta, <a href="/A181412/b181412.txt">Table of n, a(n) for n = 1..73</a> (terms < 10^24) %e A181412 1306449 is 1143 squared, and its reverse, 9446031, is a triangular number. %t A181412 trnos = Accumulate[Range[300000]]; Select[Range[210000]^2, MemberQ[trnos, FromDigits[Reverse[IntegerDigits[#]]]] &] %Y A181412 Cf. A066702, A001110, A066703, A179889, A066528, A069673. %K A181412 nonn,base %O A181412 1,2 %A A181412 _Harvey P. Dale_, Jan 30 2011 %E A181412 a(12)-a(19) from _Donovan Johnson_, Feb 12 2011