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A251944 Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row and column sum prime and every diagonal and antidiagonal sum nonprime 1
2255, 1182, 1251, 2053, 3609, 7348, 14434, 29212, 60954, 125586, 260804, 550695, 1149439, 2414347, 5147608, 10837406, 22947112, 49325294, 104571648, 222836190, 482146165, 1027815785, 2201179969, 4787010362, 10247989102, 22030788568 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 2 of A251950
LINKS
FORMULA
Empirical: a(n) = 20*a(n-3) -120*a(n-6) +231*a(n-9) -249*a(n-12) +198*a(n-15) -134*a(n-18) +55*a(n-21) for n>27
EXAMPLE
Some solutions for n=4
..3..2..2..3....3..2..0..0....0..1..1..0....2..0..3..2....0..1..1..0
..1..3..3..1....1..0..1..1....2..3..0..2....0..1..1..3....3..1..1..3
..3..0..0..3....1..3..1..1....0..1..1..0....0..1..1..0....2..0..0..2
..3..0..0..3....0..2..0..0....3..1..1..0....2..0..0..2....0..1..1..0
..1..3..3..1....1..0..1..1....2..3..0..2....0..1..1..3....3..1..1..0
..1..2..0..3....1..0..1..1....2..1..2..0....0..1..1..0....2..0..0..2
CROSSREFS
Sequence in context: A250160 A287701 A123297 * A077455 A068754 A222951
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 11 2014
STATUS
approved

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Last modified March 28 21:57 EDT 2024. Contains 371254 sequences. (Running on oeis4.)