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 A049725 #9 Aug 07 2021 01:12:56
%S A049725 1,12,29,69,116,192,229,324,418,533,695,818,923,1099,1258,1520,1687,
%T A049725 1893,2044,2315,2567,2890,3090,3377,3604,4062,4397,4659,5066,5384,
%U A049725 5697,6172,6536,7013,7293,7894,8219,8819,9180,9880
%N A049725 a(n) = Sum_{i=0..2n} (-1)^i * T(i,2n-i), array T as in A049723.
%K A049725 nonn
%O A049725 0,2
%A A049725 _Clark Kimberling_
%E A049725 Name corrected by _Sean A. Irvine_, Aug 06 2021