A275428 Number of set partitions of [n] such that ten is a multiple of each block size.
1, 1, 2, 4, 10, 27, 82, 274, 988, 3880, 16175, 72205, 340660, 1697060, 8906990, 48911059, 281486144, 1687198848, 10535484376, 68349098640, 459596780618, 3202506672898, 23052054364956, 171418420964352, 1314125642973640, 10375794542251692, 84315714183790792
Offset: 0
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..607
- Wikipedia, Partition of a set
Crossrefs
Column k=10 of A275422.
Programs
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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, 5, 10])) end: seq(a(n), n=0..30);
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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, 5, 10}}]]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, May 17 2018, translated from Maple *)
Formula
E.g.f.: exp(x+x^2/2+x^5/5!+x^10/10!).