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 A228467 #10 Jul 02 2022 11:57:15
%S A228467 0,1,4,31,492,15713,1005140,128642207,32931399852,16860748082017,
%T A228467 17265373104585556,35359467257443136671,144832360621113983218860,
%U A228467 1186466662848698493085764449,19439069659280715489603181513556,636979433408843822314618558750438559
%N A228467 Recurrence a(n) = 2^n*a(n-1) - a(n-2) with a(0)=0, a(1)=1.
%H A228467 Seiichi Manyama, <a href="/A228467/b228467.txt">Table of n, a(n) for n = 0..81</a>
%F A228467 a(n) ~ c * 2^(n^2/2 + n/2), where c = 0.4792100640621967581293535977698228585...
%t A228467 RecurrenceTable[{a[n]==2^n*a[n-1]-a[n-2],a[0]==0,a[1]==1},a,{n,0,15}]
%t A228467 nxt[{n_,a_,b_}]:={n+1,b,b*2^(n+1)-a}; NestList[nxt,{1,0,1},20][[All,2]] (* _Harvey P. Dale_, Jul 02 2022 *)
%Y A228467 Cf. A225609, A076131, A073587, A073588, A228465, A006116.
%K A228467 nonn
%O A228467 0,3
%A A228467 _Vaclav Kotesovec_, Aug 22 2013