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A285366 Sum of the entries in the fourth blocks of all set partitions of [n]. 2
4, 55, 495, 3757, 26421, 180482, 1230737, 8520912, 60531347, 444006008, 3374292280, 26605751388, 217686862402, 1847108846441, 16237616979723, 147709622593855, 1388722474550671, 13477574785475778, 134861358322272607, 1389822348657508142, 14735739124218384875 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 4..400

Wikipedia, Partition of a set

FORMULA

a(n) = A285362(n,4).

MAPLE

a:= proc(h) option remember; local b; b:=

      proc(n, m) option remember;

        `if`(n=0, [1, 0], add((p-> `if`(j=4, p+ [0,

        (h-n+1)*p[1]], p))(b(n-1, max(m, j))), j=1..m+1))

      end: b(h, 0)[2]

    end:

seq(a(n), n=4..30);

MATHEMATICA

a[h_] := a[h] = Module[{b}, b[n_, m_] := b[n, m] = If[n == 0, {1, 0}, Sum[Function[p, If[j == 4, p + {0, (h - n + 1)*p[[1]]}, p]][b[n - 1, Max[m, j]]], {j, 1, m + 1}]]; b[h, 0][[2]]];

Table[a[n], {n, 4, 30}] (* Jean-Fran├žois Alcover, May 27 2018, from Maple *)

CROSSREFS

Column k=4 of A285362.

Sequence in context: A190441 A151576 A204107 * A202163 A073352 A258793

Adjacent sequences:  A285363 A285364 A285365 * A285367 A285368 A285369

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Apr 17 2017

STATUS

approved

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Last modified August 20 20:34 EDT 2018. Contains 313927 sequences. (Running on oeis4.)