A320592 Number of partitions of n with four parts in which no part occurs more than twice.

1, 1, 3, 4, 6, 8, 12, 14, 19, 23, 29, 34, 42, 48, 58, 66, 77, 87, 101, 112, 128, 142, 160, 176, 197, 215, 239, 260, 286, 310, 340, 366, 399, 429, 465, 498, 538, 574, 618, 658, 705, 749, 801, 848, 904, 956, 1016, 1072, 1137, 1197, 1267, 1332, 1406, 1476, 1556

Offset

6,3

Links

Alois P. Heinz, Table of n, a(n) for n = 6..10000

Formula

G.f.: -(x^4-x^2-1)*x^6/((x^2+1)*(x^2+x+1)*(x+1)^2*(x-1)^4).

a(n) = floor((n^3+3*n^2-48*n+144)/144 - (n mod 2)*n/16), for n > 0. - Hoang Xuan Thanh, May 18 2026

Crossrefs

Column k=4 of A209318.

Sequence in context: A214583 A232721 A227956 * A225531 A129295 A192276

Adjacent sequences: A320589 A320590 A320591 * A320593 A320594 A320595

Keyword

nonn,easy

Author

Alois P. Heinz, Oct 16 2018

Status

approved