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 A072522 #10 Sep 15 2017 03:19:27
%S A072522 3,5,6,9,13,44,58,854,896,1194,1253,1469,1628,2170,2403,3205,3366,
%T A072522 3395,4370,4454,4676,6234,6545,6873,9165,9624,12833,17110,17450,18524,
%U A072522 24012,25025,25652,28242,37657,356750,400894,420938,561250,1347002
%N A072522 Smallest number a(n)>a(n-1) such that T(a(n-1))+T(a(n))=T(m) for some m, a(1)=3; T(i) are the triangular numbers.
%H A072522 Chai Wah Wu, <a href="/A072522/b072522.txt">Table of n, a(n) for n = 1..2401</a>
%o A072522 (PARI) p=3; print1("3, "); for(n=2, 50, t=p*(p+1)/2; for(k=p, 10^9, u=t+k*(k+1)/2; v=floor(sqrt(2*u)); if(v*(v+1)/2==u, print1(k", "); p=k; break)))
%Y A072522 Cf. A072521, A082183. Values of m are in A080824.
%K A072522 nonn
%O A072522 1,1
%A A072522 _Amarnath Murthy_, Jul 31 2002
%E A072522 Edited by _Ralf Stephan_, Mar 27 2003