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A240365
Number of 2Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or two plus the sum of the elements diagonally to its northwest, modulo 4
1
4, 15, 51, 188, 672, 2452, 8822, 32077, 115811, 420299, 1519980, 5510943, 19945570, 72279704, 261698918, 948113920, 3433420924, 12437397618, 45043913721, 163158785746, 590931290044, 2140411544446, 7752356423111, 28079348085009
OFFSET
1,1
COMMENTS
Row 2 of A240364
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +9*a(n-2) -23*a(n-3) -15*a(n-4) +30*a(n-5) +20*a(n-6) +7*a(n-7) -30*a(n-8) +a(n-9) +23*a(n-10) -8*a(n-11) -8*a(n-12)
EXAMPLE
Some solutions for n=4
..3..3..1..3....0..0..0..0....0..3..1..3....0..0..3..1....3..1..3..1
..0..2..2..2....3..1..3..1....3..3..2..0....0..0..0..2....0..0..0..2
CROSSREFS
Sequence in context: A055218 A303843 A107307 * A005492 A003013 A117202
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 04 2014
STATUS
approved