A158147 Number of nondecreasing integer sequences of length 13 with sum zero and sum of absolute values 2n.

1, 4, 9, 25, 49, 121, 224, 476, 862, 1629, 2750, 4942, 7947, 13290, 20892, 33272, 50229, 77373, 113409, 168716, 242193, 349279, 489700, 692174, 950812, 1312535, 1775675, 2406215, 3200557, 4271720, 5600464, 7359874, 9536595, 12359775, 15825600, 20285074, 25685608

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..450

Formula

a(n) = A000041(n)^2 for n <= 6.

a(n) = A000041(n)^2 - cumulative A000712(2*n-1-length), 0 <= 2*n-1-length <= floor(n/2) [empirical].

Crossrefs

Column k=13 of A389686.

Sequence in context: A229970 A038771 A158146 * A158148 A158149 A158150

Adjacent sequences: A158144 A158145 A158146 * A158148 A158149 A158150

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved