A282082 Number of n-element subsets of [n+6] having an even sum.

1, 3, 12, 44, 110, 226, 452, 868, 1519, 2485, 3976, 6216, 9324, 13524, 19320, 27192, 37389, 50391, 67188, 88660, 115258, 147862, 188188, 237692, 297115, 367913, 452816, 554064, 672792, 811240, 973488, 1162800, 1380825, 1630827, 1918620, 2248764, 2623558

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Formula

G.f.: -(x^8-4*x^7+16*x^6-28*x^5+38*x^4-28*x^3+16*x^2-4*x+1) / ((x^2+1)^4*(x-1)^7).

a(n) = A282011(n+6,n).

Example

a(0) = 1: {}.
a(1) = 3: {2}, {4}, {6}.
a(2) = 12: {1,3}, {1,5}, {1,7}, {2,4}, {2,6}, {2,8}, {3,5}, {3,7}, {4,6}, {4,8}, {5,7}, {6,8}.

Crossrefs

Cf. A282011.

Sequence in context: A366617 A290918 A012873 * A356888 A167477 A190051

Adjacent sequences: A282079 A282080 A282081 * A282083 A282084 A282085

Keyword

nonn,easy

Author

Alois P. Heinz, Feb 05 2017

Status

approved