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 A135805 #15 Nov 11 2016 21:49:28
%S A135805 1,0,0,120,330,6336,61776,785928,10456875,151099520,2339361024,
%T A135805 38655753552,678721170036,12615988058880,247449420044640,
%U A135805 5106608041235184,110596074738524661,2507849090860975488
%N A135805 Eighth column (k=7) of triangle A134832 (circular succession numbers).
%C A135805 a(n) enumerates circular permutations of {1,2,...,n+7} with exactly seven successor pairs (i,i+1). Due to cyclicity also (n+7,1) is a successor pair.
%D A135805 Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=7.
%H A135805 G. C. Greubel, <a href="/A135805/b135805.txt">Table of n, a(n) for n = 0..443</a>
%F A135805 a(n) = binomial(n+7,7)*A000757(n), n>=0.
%F A135805 E.g.f.: (d^7/dx^7) (x^7/7!)*(1-log(1-x))/e^x.
%e A135805 a(0)=1 because from the 7!/7 = 720 circular permutations of n=7 elements only one, namely (1,2,3,4,5,6,7), has seven successors.
%t A135805 f[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := f[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[a[n, 7], {n, 7, 25}] (* _G. C. Greubel_, Nov 10 2016 *)
%Y A135805 Cf. A135804 (column k=6), A135806 (column k=8).
%K A135805 nonn,easy
%O A135805 0,4
%A A135805 _Wolfdieter Lang_, Jan 21 2008