A178298 Number of collinear point triples in a 5 X 5 X 5 X... n-dimensional cubic grid.

0, 10, 152, 1858, 21680, 253690, 3023432, 36785458, 455700320, 5725140970

Offset: 0

Author

R. H. Hardin, suggested by R. J. Mathar in the Sequence Fans Mailing List, May 24 2010

Keywords

• nonn

Formula

From R. J. Mathar May 24 2010: (Start)

Conjecture: a(n) = 7^n - 5^(n+1)/2 + 13^n/2 + 9^n.

Conjecture: a(n) = 34*a(n-1) - 416*a(n-2) + 2174*a(n-3) - 4095*a(n-4).

Conjectured g.f.: 2*x*(5-94*x+425*x^2)/((9*x-1)*(13*x-1)*(7*x-1)*(5*x-1)).

(End)