A158172 Number of nondecreasing integer sequences of length 38 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, 393126, 627246, 1003930, 1574776, 2479891, 3831797, 5929194, 9048589, 13797791, 20784120, 31291083, 46586043, 69266085, 102051440

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n=1..222

Formula

a(n) = A000041(n)^2 for n <= 19.

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: A158169 A158170 A158171 * A158173 A158174 A158175

Adjacent sequences: A158169 A158170 A158171 * A158173 A158174 A158175

Keyword

nonn

Author

R. H. Hardin, Mar 13 2009

Status

approved