OFFSET
1,2
LINKS
J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).
FORMULA
Numbers of the form (n^2+n+k^2-k+4kn)/2, n>=1, k>=0. - Bob Selcoe, Nov 14 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved