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 A328334 #11 Oct 12 2019 18:51:24 %S A328334 1,0,4,2,-2,32,10,-34,256,26,1024,590,-278,8192,3262,-6598,65536, %T A328334 12974,262144,169994,-14306,2097152,1005658,-1177330,16777216,4856618, %U A328334 -18984578,134217728,10155130,536870912,298900846,-177039286,4294967296,1616365790,-3740837222 %N A328334 Forward difference of difference between 2^n and the next smaller power of 3. %C A328334 a(n) is even for n >= 1. %H A328334 Alois P. Heinz, <a href="/A328334/b328334.txt">Table of n, a(n) for n = 0..3323</a> %F A328334 a(n) = A063005(n+1) - A063005(n). %p A328334 b:= proc(n) option remember; (t-> t-3^ilog[3](t))(2^n) end: %p A328334 a:= n-> b(n+1)-b(n): %p A328334 seq(a(n), n=0..40); %Y A328334 Cf. A063005. %K A328334 sign %O A328334 0,3 %A A328334 _Alois P. Heinz_, Oct 12 2019