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A252450 Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 2 4 6 or 7 1
661, 228, 323, 747, 1731, 3938, 9013, 20820, 48122, 111079, 256713, 594491, 1378368, 3198521, 7429788, 17277634, 40219359, 93711513, 218547089, 510131978, 1191760983, 2786416350, 6519837310, 15266746829, 35773378779, 83880640135 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A252457

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -3*a(n-2) +9*a(n-3) -9*a(n-4) +4*a(n-5) -22*a(n-6) -14*a(n-7) -19*a(n-8) -8*a(n-9) +8*a(n-10) +18*a(n-11) +24*a(n-12) +20*a(n-13) +6*a(n-14) -4*a(n-15) -8*a(n-16) -4*a(n-17) for n>20

EXAMPLE

Some solutions for n=4

..2..0..3....1..3..1....3..3..2....2..3..3....3..3..3....3..2..3....2..3..3

..3..3..3....1..1..1....2..3..3....3..3..3....3..3..3....3..3..3....3..3..3

..3..2..3....1..1..1....3..3..3....3..3..3....3..3..3....3..3..3....3..3..3

..3..3..3....3..1..1....3..2..3....3..2..3....3..3..2....3..3..3....3..3..3

..3..3..2....1..1..3....3..3..3....3..3..3....3..3..3....2..3..3....3..3..3

..2..3..3....1..1..1....2..3..3....3..3..2....3..2..3....3..2..3....3..3..2

CROSSREFS

Sequence in context: A235553 A342994 A252457 * A252449 A252401 A171394

Adjacent sequences:  A252447 A252448 A252449 * A252451 A252452 A252453

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 17 2014

STATUS

approved

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Last modified May 28 18:24 EDT 2022. Contains 354122 sequences. (Running on oeis4.)