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 A273657 #4 May 27 2016 12:22:09
%S A273657 877,26104,463212,6409320,76595310,832521096,8480449692,82506827832,
%T A273657 776400941745,7128606776720,64261876786536,571350882111984,
%U A273657 5026991629995036,43878686837771760,380672326962043560,3287071510635218064,28280022744131688519,242602886107926614952
%N A273657 Number of forests of labeled rooted trees of height at most 1, with n labels, seven of which are used for root nodes and any root may contain >= 1 labels.
%H A273657 Alois P. Heinz, <a href="/A273657/b273657.txt">Table of n, a(n) for n = 7..1000</a>
%F A273657 E.g.f.: x^7/7! * Sum_{j=0..7} Stirling2(7,j)*exp(x)^j.
%F A273657 a(n) = C(n,7) * Sum_{j=0..7} Stirling2(7,j) * j^(n-7).
%p A273657 a:= n-> binomial(n,7)*add(Stirling2(7,j)*j^(n-7), j=0..7):
%p A273657 seq(a(n), n=7..40);
%Y A273657 Column k=7 of A143396.
%K A273657 nonn
%O A273657 7,1
%A A273657 _Alois P. Heinz_, May 27 2016