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 A386399 #9 Jul 21 2025 12:12:38
%S A386399 1,2,4,7,13,23,43,80,156,309,638,1348,2949,6607,15206,35720,85625,
%T A386399 208588,515787,1291316,3269194,8355832,21539988,55942920,146271594,
%U A386399 384746580,1017522228,2704227858,7219183490,19351410860,52068524665,140588391713,380824067016
%N A386399 Number of forests with at most n unlabeled nodes.
%H A386399 Alois P. Heinz, <a href="/A386399/b386399.txt">Table of n, a(n) for n = 0..1000</a>
%F A386399 G.f.: exp(sum_{k>0} B(x^k)/k ) / (1-x), where B(x) = x + x^2 + x^3 + 2*x^4 + 3*x^5 + 6*x^6 + 11*x^7 + ... = C(x)-1 and C is the g.f. for A000055.
%Y A386399 Partial sums of A005195.
%Y A386399 Cf. A000272, A002807, A006897, A054548, A137917, A367863, A372176.
%K A386399 nonn,easy
%O A386399 0,2
%A A386399 _Max Alekseyev_, Jul 20 2025