OFFSET
0,4
COMMENTS
Number of ways to choose 4 points forming a regular tetrahedron out of the binomial(n+2,3) points in a regular tetrahedral grid.
The tetrahedra defined by the four points may have any orientation.
Similar to A216173, which differs from the present sequence in a mysterious way.
FORMULA
It would be nice to have a g.f. - N. J. A. Sloane, Mar 21 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Warren D. Smith, Mar 21 2016; more terms Mar 23 2016
EXTENSIONS
a(21) changed from 24130 to 21430 by Anthony Guttmann, Mar 07 2023
STATUS
approved