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A256022 Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1. 1
33, 68, 154, 352, 798, 1804, 4086, 9304, 21194, 48176, 109506, 249120, 566754, 1289056, 2931842, 6668688, 15168650, 34502104, 78476674, 178499728, 406009530, 923494792, 2100545026, 4777818256, 10867446266, 24718685528, 56224184050 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +4*a(n-3) -2*a(n-6) -4*a(n-7) +2*a(n-9) for n>10.
Empirical g.f.: x*(33 + 2*x + 51*x^2 - 20*x^3 - 24*x^4 - 56*x^5 - 66*x^6 + 12*x^7 + 36*x^8 + 2*x^9) / ((1 - x)*(1 - x - 4*x^3 - 4*x^4 - 4*x^5 - 2*x^6 + 2*x^7 + 2*x^8)). - Colin Barker, Dec 20 2018
EXAMPLE
Some solutions for n=4:
..1..0..1....0..1..1....0..1..1....1..1..0....0..1..1....1..1..1....1..1..1
..1..1..1....1..1..0....1..1..1....1..1..1....1..1..1....1..0..1....1..1..1
..1..1..0....1..1..1....1..0..1....1..1..1....1..1..1....1..1..1....1..0..1
..0..1..1....1..1..1....1..1..1....1..1..0....0..1..1....1..1..0....1..1..1
..1..1..1....0..1..1....1..1..1....0..1..1....1..1..1....0..1..1....0..1..1
..1..0..1....1..1..1....1..0..1....1..1..1....1..0..1....1..0..1....1..1..0
CROSSREFS
Column 1 of A256029.
Sequence in context: A032661 A256029 A055078 * A044135 A044516 A015722
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 13 2015
STATUS
approved

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Last modified June 20 01:44 EDT 2024. Contains 373510 sequences. (Running on oeis4.)