A243121 Number of compositions of n in which the maximal multiplicity of parts equals 4.

1, 0, 5, 5, 21, 40, 100, 210, 396, 870, 1790, 3510, 6681, 13100, 25320, 47835, 87126, 166195, 299375, 542595, 991036, 1775935, 3145270, 5487805, 9852046, 17092310, 29561070, 50696690, 88015196, 150446590, 256066280, 428469220, 727919426, 1224816005, 2043828145

Offset

4,3

Links

Alois P. Heinz, Table of n, a(n) for n = 4..1000

Formula

a(n) = A243082(n) - A232464(n) = A243081(n,4) - A243081(n,3).

Maple

b:= proc(n, i, p, k) option remember; `if`(n=0, p!, `if`(i<1, 0,
      add(b(n-i*j, i-1, p+j, k)/j!, j=0..min(n/i, k))))
    end:
a:= n-> b(n$2, 0, 4) -b(n$2, 0, 3):
seq(a(n), n=4..50);

Crossrefs

Column k=4 of A242447.

Sequence in context: A283046 A147254 A241864 * A007028 A318960 A097336

Adjacent sequences: A243118 A243119 A243120 * A243122 A243123 A243124

Keyword

nonn

Author

Alois P. Heinz, May 29 2014

Status

approved