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A215869 Number of permutations of 0..floor((n*9-2)/2) on odd squares of an nX9 array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing 1
1, 14, 290, 11694, 307874, 14296434, 386699176, 18255280444, 494952307400, 23397688110992, 634501639410480, 29997930933948284, 813501010455768664, 38461009542931961924, 1043008988814913191696, 49311812528326463481148 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 9 of A215870
LINKS
FORMULA
Empirical: a(n) = 1385*a(n-2) -131648*a(n-4) -318070*a(n-6) -4160916*a(n-8) -1097892*a(n-10) +648*a(n-12)
EXAMPLE
Some solutions for n=4
..x..0..x..2..x..4..x..8..x....x..0..x..2..x..4..x..6..x
..1..x..3..x..5..x.11..x.12....1..x..3..x..7..x.10..x.13
..x..6..x..7..x.13..x.14..x....x..5..x..9..x.12..x.15..x
..9..x.10..x.15..x.16..x.17....8..x.11..x.14..x.16..x.17
CROSSREFS
Sequence in context: A233069 A181192 A227580 * A262740 A158475 A116165
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 25 2012
STATUS
approved

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Last modified February 29 11:30 EST 2024. Contains 370425 sequences. (Running on oeis4.)