OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..400 (terms 1..210 from R. H. Hardin) [It was suggested that the initial terms of this b-file were wrong, but in fact they are correct. - N. J. A. Sloane, Jan 19 2019]
FORMULA
a(n) ~ sqrt(3) * 15^n / (4*sqrt(7*Pi*n)). - Vaclav Kotesovec, Dec 15 2018
EXAMPLE
Some solutions for n=5
.-6....6....2...-1...-4...-5...-2...-2....4...-6....2....7...-5...-5....3....5
.-2....0....7...-3....2....6...-3....7...-4...-2...-7...-3....6....2...-3...-7
..0...-6...-5...-2....6....5....5...-5...-6....5....5....1...-4....4....1...-4
..2...-2...-4....0...-7...-5....6...-7....6....6...-5....1....4....5...-3....7
..6....2....0....6....3...-1...-6....7....0...-3....5...-6...-1...-6....2...-1
MAPLE
seq(add((-1)^k*binomial(n, k)*binomial(8*n-15*k-1, n-1), k = 0..floor(n/2)), n = 0..20); # Peter Bala, Oct 19 2024
MATHEMATICA
a[n_] := If[n==0, 1, Coefficient[Expand[Sum[x^k, {k, 0, 14}]^n], x^(7n)]]; Array[a, 25, 0] (* Amiram Eldar, Dec 14 2018 *)
PROG
(PARI) {a(n) = polcoeff((sum(k=0, 14, x^k))^n, 7*n, x)} \\ Seiichi Manyama, Dec 14 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 02 2011
EXTENSIONS
a(0)=1 prepended by Seiichi Manyama, Dec 14 2018
STATUS
approved