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 A305572 #11 Dec 06 2021 03:08:17
%S A305572 1,0,2,0,2,4,2,0,10,4,2,32,2,4,42,0,2,228,2,32,138,4,2,1536,34,4,1514,
%T A305572 32,2,3940,2,0,2058,4,162,102944,2,4,8202,1536,2,51940,2,32,207370,4,
%U A305572 2,3538944,130,3204,131082,32,2,15668836,2082,1536,524298,4,2,54327840
%N A305572 a(n) = (-1)^(n-1) + Sum_{d|n, d>1} a(n/d)^d.
%H A305572 Antti Karttunen, <a href="/A305572/b305572.txt">Table of n, a(n) for n = 1..6911</a>
%F A305572 a(n) = Sum_t (-1)^(n-k) where the sum is over all same-trees of weight n (see A281145 for definition) and k is the number of leaves.
%t A305572 a[n_]:=a[n]=(-1)^(n-1)+Sum[a[n/y]^y,{y,Divisors[n]//Rest}];
%t A305572 Array[a,40]
%o A305572 (PARI) A305572(n) = ((-1)^(n-1) + sumdiv(n,d,if(d==1,0,A305572(n/d)^d))); \\ _Antti Karttunen_, Dec 05 2021
%Y A305572 Cf. A196545, A273873, A281145, A289078, A289079, A289501, A290261, A290971, A291441, A300862-A300866.
%K A305572 nonn
%O A305572 1,3
%A A305572 _Gus Wiseman_, Jun 05 2018