login
A266931
Number of n X 4 binary arrays with rows lexicographically nondecreasing and columns lexicographically nondecreasing and row sums nondecreasing and column sums nonincreasing.
1
2, 5, 12, 35, 100, 288, 794, 2077, 5110, 11869, 26086, 54543, 108999, 209148, 386883, 692473, 1203061, 2034487, 3357115, 5416951, 8563297, 13284702, 20254831, 30390893, 44926915, 65505045, 94288435, 134099783, 188589873, 262441858
OFFSET
1,1
COMMENTS
Column 4 of A266935.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +3*a(n-2) -4*a(n-3) -9*a(n-4) -a(n-5) +19*a(n-6) +13*a(n-7) -13*a(n-8) -25*a(n-9) -11*a(n-10) +15*a(n-11) +22*a(n-12) +17*a(n-13) -4*a(n-14) -23*a(n-15) -23*a(n-16) -4*a(n-17) +17*a(n-18) +22*a(n-19) +15*a(n-20) -11*a(n-21) -25*a(n-22) -13*a(n-23) +13*a(n-24) +19*a(n-25) -a(n-26) -9*a(n-27) -4*a(n-28) +3*a(n-29) +2*a(n-30) -a(n-31).
EXAMPLE
Some solutions for n=4
..0..0..1..1....0..0..1..1....0..0..0..0....0..0..0..1....0..0..0..1
..1..1..0..1....1..1..0..0....0..0..0..1....0..0..1..0....1..1..1..0
..1..1..1..0....1..1..0..1....0..0..1..0....1..1..0..0....1..1..1..0
..1..1..1..1....1..1..1..0....1..1..0..0....1..1..0..0....1..1..1..0
CROSSREFS
Cf. A266935.
Sequence in context: A350441 A181899 A131267 * A148286 A075202 A075203
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2016
STATUS
approved