A158159 Number of nondecreasing integer sequences of length 25 with sum zero and sum of absolute values 2n.

1, 4, 9, 25, 49, 121, 225, 484, 900, 1764, 3136, 5929, 10200, 18217, 30938, 53222, 87775, 147014, 237016, 385812, 610985, 969505, 1505188, 2343756, 3574348, 5453815, 8193561, 12288418, 18176135, 26851525, 39163566, 57009656, 82117074

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..263

Formula

a(n) = A000041(n)^2 for n <= 12.

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

Crossrefs

Sequence in context: A158156 A158157 A158158 * A158160 A158161 A158162

Adjacent sequences: A158156 A158157 A158158 * A158160 A158161 A158162

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved