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A252026 Number of (n+2)X(2+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 2 or 4 1
227, 323, 781, 1929, 5285, 14831, 41745, 117867, 332997, 941237, 2660915, 7523177, 21271317, 60144341, 170058799, 480846469, 1359611219, 3844354431, 10870074659, 30735606793, 86906264441, 245731273709, 694815999081, 1964622840375 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A252032

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) -a(n-2) +6*a(n-3) -12*a(n-4) -3*a(n-5) -a(n-6) +6*a(n-7) +a(n-8) +6*a(n-9) +a(n-10) +3*a(n-11) -3*a(n-12) -3*a(n-13) -2*a(n-14) for n>18

EXAMPLE

Some solutions for n=4

..2..2..2..1....2..0..1..2....1..2..2..2....2..2..1..2....2..2..2..2

..2..2..2..2....0..1..2..2....2..1..2..2....2..1..2..2....2..2..2..2

..2..2..2..2....1..2..2..1....2..2..1..2....1..2..2..2....2..2..2..2

..1..2..2..2....2..2..1..2....1..2..2..1....2..2..2..2....2..2..1..2

..2..2..2..2....2..1..2..2....0..1..2..2....2..1..2..2....1..2..2..2

..2..1..2..2....1..2..2..1....0..2..1..2....2..2..2..1....2..2..2..1

CROSSREFS

Sequence in context: A333425 A142261 A117458 * A210513 A142842 A142545

Adjacent sequences:  A252023 A252024 A252025 * A252027 A252028 A252029

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 12 2014

STATUS

approved

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Last modified October 19 16:25 EDT 2021. Contains 348091 sequences. (Running on oeis4.)