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 A283831 #8 Mar 24 2017 06:48:08
%S A283831 1,-12,3024,-4390848,21224560896,-257991277243392,6628234834692624384,
%T A283831 -319729080846260095008768,26571747463798134334265819136,
%U A283831 -3564202847752289659513902717468672,733070216072136922924207670741034860544,-221829664053602095461018886102097997267468288
%N A283831 Take every fourth term of A104203.
%H A283831 Vincenzo Librandi, <a href="/A283831/b283831.txt">Table of n, a(n) for n = 0..57</a>
%o A283831 (PARI) x='x+O('x^66); v=Vec(serlaplace(serreverse( intformal( 1/sqrt(1-x^4))))); vector(#v\4,n,v[4*n-3]) \\ _Joerg Arndt_, Mar 24 2017
%Y A283831 Cf. A104203.
%K A283831 sign
%O A283831 0,2
%A A283831 _N. J. A. Sloane_, Mar 20 2017
%E A283831 a(9) - a(11) from _Vincenzo Librandi_, Mar 24 2017