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 A101157 #25 May 02 2018 10:09:19
%S A101157 1,3,5,2,9,11,13,15,3,19,6,5,25,27,29,4,33,10,37,39,14,43,45,7,5,9,53,
%T A101157 55,57,59,61,18,65,67,15,6,18,75,22,9,81,83,15,87,21,26,12,95,7,99,
%U A101157 101,33,30,107,109,111,22,25,117,11,121,42,125,8,129
%N A101157 Let j be the smallest integer for which n+(n+1)+...+(n+j) is a square, say k^2; then a(n)=k.
%C A101157 Basis for sequence is shortest arithmetic sequence with initial term n and difference 1 that sums to a perfect square. Cf. A100251, A100252, A100253, A100254.
%C A101157 a(n) is the least k>0 such that triangular(n-1) + k^2 is a triangular number. - _Alex Ratushnyak_, May 17 2013
%H A101157 Shawn A. Broyles, <a href="/A101157/b101157.txt">Table of n, a(n) for n = 1..1000</a>
%F A101157 n+(n+1)+...+(n+A101160(n)) = n+(n+1)+...+A101159(n) = a(n)^2 = A101158(n).
%F A101157 a(n^2) = n. - _Michel Marcus_, Jun 28 2013
%e A101157 a(11)=6 since 11+12+13 = 6^2.
%o A101157 (PARI) a(n) = {j = 0; while(! issquare(v=sum(k=0, j, n+k)), j++); sqrtint(v);} \\ _Michel Marcus_, Sep 01 2013
%Y A101157 Cf. A101158, A101159, A101160.
%K A101157 nonn
%O A101157 1,2
%A A101157 _Charlie Marion_, Dec 29 2004
%E A101157 More terms from _Michel Marcus_, Jun 28 2013