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A301665
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Number of nX4 0..1 arrays with every element equal to 1, 2 or 4 horizontally or vertically adjacent elements, with upper left element zero.
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1
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2, 23, 118, 564, 2793, 14394, 71564, 359659, 1808256, 9076074, 45607585, 229124216, 1151098126, 5783024867, 29053401570, 145961054556, 733293062029, 3683989357618, 18507978344520, 92982190589347, 467132961135876
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 3*a(n-1) +15*a(n-2) -6*a(n-3) -91*a(n-4) -75*a(n-5) +327*a(n-6) +398*a(n-7) -880*a(n-8) -1862*a(n-9) -823*a(n-10) +79*a(n-11) +5465*a(n-12) +26064*a(n-13) +45144*a(n-14) -31786*a(n-15) -99377*a(n-16) -89293*a(n-17) +55985*a(n-18) -111034*a(n-19) -138395*a(n-20) +141455*a(n-21) +486139*a(n-22) +96486*a(n-23) -536176*a(n-24) +16636*a(n-25) +98232*a(n-26) +573306*a(n-27) -822404*a(n-28) +47656*a(n-29) +698032*a(n-30) +48550*a(n-31) -264890*a(n-32) -1009366*a(n-33) +282680*a(n-34) +950924*a(n-35) -62788*a(n-36) -370362*a(n-37) +6650*a(n-38) -1020118*a(n-39) +1292800*a(n-40) -896852*a(n-41) +1410204*a(n-42) -572266*a(n-43) -344184*a(n-44) -135916*a(n-45) -198212*a(n-46) +723258*a(n-47) -188503*a(n-48) -34287*a(n-49) -130327*a(n-50) +23396*a(n-51) +62935*a(n-52) -53445*a(n-53) +2017*a(n-54) +6884*a(n-55) +16010*a(n-56) +6076*a(n-57) -4473*a(n-58) -7867*a(n-59) -461*a(n-60) +2650*a(n-61) +830*a(n-62) -536*a(n-63) -391*a(n-64) +73*a(n-65) +91*a(n-66) +12*a(n-67) -13*a(n-68) -3*a(n-69) +a(n-70)
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EXAMPLE
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Some solutions for n=5
..0..1..0..0. .0..0..0..0. .0..0..0..0. .0..0..1..0. .0..0..0..1
..0..1..0..1. .0..1..1..1. .1..1..1..0. .0..1..1..0. .1..1..0..1
..0..0..1..1. .1..1..0..1. .0..0..0..1. .1..1..0..1. .0..1..1..1
..1..0..0..0. .0..0..0..0. .0..1..1..1. .0..0..0..1. .0..0..0..0
..1..1..1..1. .1..1..0..0. .0..1..0..0. .0..1..1..1. .1..1..1..0
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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