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A251888 Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and column sum not 2 3 6 or 7 and every diagonal and antidiagonal sum 2 3 6 or 7. 1
1664, 1232, 602, 530, 594, 790, 1182, 1670, 2474, 3890, 5642, 8594, 13922, 20498, 31778, 52418, 77858, 121922, 203138, 303170, 477314, 799490, 1196162, 1888514, 3171842, 4751618, 7512578, 12635138, 18940418, 29967362, 50436098, 75629570 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 6*a(n-3) - 6*a(n-4) - 8*a(n-6) + 8*a(n-7) for n>14.

Empirical g.f.: 2*x*(832 - 216*x - 315*x^2 - 5028*x^3 + 1328*x^4 + 1988*x^5 + 7068*x^6 - 1676*x^7 - 2706*x^8 - 756*x^9 - 332*x^10 - 152*x^11 - 16*x^12 - 16*x^13) / ((1 - x)*(1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Nov 30 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 2 of A251894.

Sequence in context: A340923 A104019 A054810 * A251785 A234976 A303643

Adjacent sequences:  A251885 A251886 A251887 * A251889 A251890 A251891

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 10 2014

STATUS

approved

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Last modified September 17 19:58 EDT 2021. Contains 347489 sequences. (Running on oeis4.)