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A252081 Number of (n+2)X(1+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 1 3 or 4 1
64, 130, 295, 687, 1591, 3650, 8389, 19412, 45002, 104255, 241737, 561451, 1305496, 3038129, 7076836, 16500354, 38507303, 89941465, 210246081, 491853090, 1151508703, 2697778070, 6324654030, 14836947029, 34826937451, 81796528951 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A252088

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>18

EXAMPLE

Some solutions for n=4

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

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

..2..2..2....2..2..2....0..2..0....0..0..0....0..0..2....0..0..2....0..0..0

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

..2..2..2....2..2..2....0..0..0....0..0..0....0..0..0....0..0..0....0..2..0

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

CROSSREFS

Sequence in context: A235058 A252088 A211254 * A068410 A250654 A223063

Adjacent sequences:  A252078 A252079 A252080 * A252082 A252083 A252084

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 13 2014

STATUS

approved

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Last modified January 24 17:24 EST 2021. Contains 340411 sequences. (Running on oeis4.)