A178297 Number of collinear point 6-tuples in a 7 X 7 X 7 X... n-dimensional cubic grid.

0, 7, 116, 1459, 16520, 177727, 1861436, 19230379, 197501840

Offset

0,2

Links

Table of n, a(n) for n=0..8.

Formula

Conjectures from R. J. Mathar, May 24 2010: (Start)

a(n) = 11^n/2+5*9^n/2-3*7^n.

a(n) = 27*a(n-1) - 239*a(n-2) + 693*a(n-3).

G.f.: x*(-7+73*x)/((11*x-1)*(7*x-1)*(9*x-1)). (End)

Crossrefs

Sequence in context: A063399 A220181 A328813 * A285394 A339390 A376042

Adjacent sequences: A178294 A178295 A178296 * A178298 A178299 A178300

Keyword

nonn,more

Author

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

Status

approved