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A350191
Number of ways of placing maximum number of nonattacking rooks on a triangular board with edge-length n (not counting rotations and reflections as distinct).
3
1, 1, 1, 1, 5, 3, 1, 45, 29, 5, 807, 422, 29, 20022, 8270, 224, 642162, 211848, 3012
OFFSET
1,5
COMMENTS
a(n) = A350041(n) for n <> 10,13,16,19,...
Conjecture: a(3*n-2) = A309260(n). There is a nice analogy with A289893(3*n+1) = A002047(n).
CROSSREFS
Sequence in context: A352136 A143410 A114344 * A350041 A317674 A201333
KEYWORD
nonn,more,hard
AUTHOR
Vaclav Kotesovec, Dec 19 2021
STATUS
approved