A321774 Number of compositions of n into parts with distinct multiplicities and with exactly four parts.

1, 4, 4, 8, 5, 8, 12, 12, 9, 16, 16, 16, 17, 20, 20, 24, 21, 24, 28, 28, 25, 32, 32, 32, 33, 36, 36, 40, 37, 40, 44, 44, 41, 48, 48, 48, 49, 52, 52, 56, 53, 56, 60, 60, 57, 64, 64, 64, 65, 68, 68, 72, 69, 72, 76, 76, 73, 80, 80, 80, 81, 84, 84, 88, 85, 88, 92

Offset

4,2

Links

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

Formula

Conjectures from Colin Barker, Dec 11 2018: (Start)

G.f.: x^4*(1 + 4*x + 4*x^2 + 7*x^3) / ((1 - x)^2*(1 + x)*(1 + x^2)*(1 + x + x^2)).

a(n) = a(n-3) + a(n-4) - a(n-7) for n>10.

(End)

Crossrefs

Column k=4 of A242887.

Sequence in context: A339756 A163369 A290841 * A254267 A028266 A275982

Adjacent sequences: A321771 A321772 A321773 * A321775 A321776 A321777

Keyword

nonn

Author

Alois P. Heinz, Nov 18 2018

Status

approved