A178295 Number of collinear point 4-tuples in a 5 X 5 X 5 X... n-dimensional cubic grid

0, 5, 64, 629, 5632, 48485, 410944, 3470549, 29389312, 250334405

Offset

0,2

Links

Table of n, a(n) for n=0..9.

Formula

Conjecture: a(n) = 9^n/2+3*7^n/2-2*5^n. a(n)= +21*a(n-1) -143*a(n-2) +315*a(n-3). G.f.: x*(-5+41*x)/((9*x-1)*(7*x-1)*(5*x-1)). [R. J. Mathar, May 24 2010]

Crossrefs

Sequence in context: A180787 A222455 A351855 * A054937 A302993 A266095

Adjacent sequences: A178292 A178293 A178294 * A178296 A178297 A178298

Keyword

nonn

Author

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

Status

approved