login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A007402
No-3-in-line problem for equilateral triangle array of side n.
(Formerly M0123)
1
1, 1, 2, 1, 2, 15, 1, 5, 7, 971, 20, 276
OFFSET
1,3
REFERENCES
R. H. Buchholz, personal communication.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
CROSSREFS
Sequence in context: A048296 A016542 A242085 * A334505 A375955 A251731
KEYWORD
nonn,nice
STATUS
approved