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A275426 Number of set partitions of [n] such that eight is a multiple of each block size. 2
1, 1, 2, 4, 11, 31, 106, 372, 1500, 6220, 28696, 136016, 702802, 3727946, 21253324, 124231096, 772458366, 4918962462, 33061094812, 227303566648, 1639389311906, 12082068225466, 92951836390172, 729991698024568, 5960615982017512, 49636995406898376 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..604

Wikipedia, Partition of a set

FORMULA

E.g.f.: exp(x+x^2/2+x^4/24+x^8/8!).

MAPLE

a:= proc(n) option remember; `if`(n=0, 1, add(

      `if`(j>n, 0, a(n-j)*binomial(n-1, j-1)), j=[1, 2, 4, 8]))

    end:

seq(a(n), n=0..30);

MATHEMATICA

a[n_] := a[n] = If[n == 0, 1, Sum[If[j > n, 0, a[n-j]*Binomial[n-1, j-1]], {j, {1, 2, 4, 8}}]];

Table[a[n], {n, 0, 30}] (* Jean-Fran├žois Alcover, May 17 2018, translated from Maple *)

CROSSREFS

Column k=8 of A275422.

Sequence in context: A148169 A110140 A190452 * A115625 A056323 A081557

Adjacent sequences:  A275423 A275424 A275425 * A275427 A275428 A275429

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 27 2016

STATUS

approved

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Last modified October 17 14:47 EDT 2019. Contains 328114 sequences. (Running on oeis4.)