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A303042
Number of 4Xn 0..1 arrays with every element equal to 0, 1, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
8, 10, 35, 74, 234, 869, 2926, 8500, 27931, 96592, 325288, 1051261, 3506796, 11931140, 40248675, 134258666, 451774036, 1530339997, 5170509004, 17416735952, 58815737695, 199037081262, 673067713068, 2274228205231, 7690132113108
OFFSET
1,1
COMMENTS
Row 4 of A303040.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +4*a(n-2) -6*a(n-3) +73*a(n-4) -240*a(n-5) -341*a(n-6) +480*a(n-7) -2065*a(n-8) +7402*a(n-9) +10592*a(n-10) -13225*a(n-11) +34742*a(n-12) -123483*a(n-13) -182747*a(n-14) +195467*a(n-15) -385754*a(n-16) +1222527*a(n-17) +1964345*a(n-18) -1804329*a(n-19) +2869079*a(n-20) -7219556*a(n-21) -13753473*a(n-22) +10685789*a(n-23) -13899268*a(n-24) +23713166*a(n-25) +62811529*a(n-26) -38417170*a(n-27) +40787608*a(n-28) -30283629*a(n-29) -175703207*a(n-30) +73169804*a(n-31) -64635290*a(n-32) -46685202*a(n-33) +254565055*a(n-34) -64087923*a(n-35) +48130794*a(n-36) +186503318*a(n-37) -110678378*a(n-38) +80503265*a(n-39) +10154339*a(n-40) -180320138*a(n-41) -40411189*a(n-42) -123008803*a(n-43) -84599828*a(n-44) +51373230*a(n-45) +938426*a(n-46) +4023387*a(n-47) +14582167*a(n-48) -4415294*a(n-49) +1720928*a(n-50) -285856*a(n-51) +1699116*a(n-52) +701304*a(n-53) -579560*a(n-54) +490896*a(n-55) -345696*a(n-56) -44480*a(n-57) +34144*a(n-58) -47104*a(n-59) +18304*a(n-60) -2048*a(n-61) for n>62
EXAMPLE
Some solutions for n=5
..0..1..0..1..0. .0..1..1..1..0. .0..1..0..0..1. .0..1..0..0..1
..1..1..0..1..1. .1..1..1..1..1. .0..1..1..1..1. .0..1..0..1..0
..0..1..0..1..0. .0..1..1..1..0. .0..1..0..0..0. .0..1..0..1..0
..0..1..0..0..0. .0..1..0..1..0. .0..1..0..1..1. .1..0..0..1..0
CROSSREFS
Cf. A303040.
Sequence in context: A223587 A302312 A245199 * A242506 A302879 A303527
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 17 2018
STATUS
approved