A158175 Number of nondecreasing integer sequences of length 41 with sum zero and sum of absolute values 2n.

1, 4, 9, 25, 49, 121, 225, 484, 900, 1764, 3136, 5929, 10201, 18225, 30976, 53361, 88209, 148225, 240100, 393129, 627263, 1003996, 1574987, 2480486, 3833330, 5932881, 9056968, 13815957, 20821892, 31366853, 46733017, 69543060, 102559313

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..204

Formula

a(n) = A000041(n)^2 for n <= 20.

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

Crossrefs

Cf. A000041, A000712.

Sequence in context: A158172 A158173 A158174 * A158176 A158177 A158178

Adjacent sequences: A158172 A158173 A158174 * A158176 A158177 A158178

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved