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 A179889 #25 Jun 21 2015 14:05:39 %S A179889 1,10,630,52650,165600,986310,9446031,9485190,10693000,1270004401, %T A179889 14214075921,140884670790,1809702709101,4614899724711,6766532724546, %U A179889 9802814901400,10210140486640,14287075542460,52657436563056,98855178542676 %N A179889 Triangular numbers whose reverse is a square (possibly with fewer digits). %H A179889 Giovanni Resta, <a href="/A179889/b179889.txt">Table of n, a(n) for n = 1..36</a> (terms < 2*10^24) %e A179889 9446031 is triangular and 1306449 is a square. %t A179889 trnos=Accumulate[Range[14070000]]; %t A179889 sqnoQ[n_]:=IntegerQ[Sqrt[FromDigits[Reverse[IntegerDigits[n]]]]] %t A179889 Select[trnos,sqnoQ] (* _Harvey P. Dale_, Jan 31 2011 *) %Y A179889 A variant of A066703. Cf. A069673, A181412, A066528. %K A179889 base,nonn %O A179889 1,2 %A A179889 _Harvey P. Dale_, Jan 30 2011 %E A179889 More terms from _Harvey P. Dale_, Jan 31 2011