A178353 Number of collinear point 4-tuples in a 7 X 7 X 7 X ... n-dimensional cubic grid

0, 35, 660, 9767, 135240, 1856075, 25897500, 371453327, 5493496080, 83634563315

Offset

0,2

Links

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

Formula

Conjecture: a(n) = 3*13^n/2+3*11^n+9^(n+1)/2-19*7^n/2+17^n/2 ; a(n) = +57*a(n-1) -1270*a(n-2) +13830*a(n-3) -73609*a(n-4) +153153*a(n-5). G.f: x*(-35+1335*x-16597*x^2+67329*x^3) / ( (11*x-1)*(13*x-1)*(17*x-1)*(9*x-1)*(7*x-1) ). [R. J. Mathar May 25 2010]

Crossrefs

Sequence in context: A162384 A126925 A010987 * A202127 A175774 A112504

Adjacent sequences: A178350 A178351 A178352 * A178354 A178355 A178356

Keyword

nonn

Author

R. H. Hardin, suggested by R. J. Mathar in the Sequence Fans Mailing List, May 25 2010

Status

approved