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A302363
Number of nX4 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
1, 20, 20, 77, 209, 774, 3143, 13556, 60280, 272792, 1243804, 5692133, 26100174, 119782344, 549950950, 2525484907, 11598683442, 53271277746, 244673796303, 1123793697954, 5161643580014, 23707760958131, 108891405413647
OFFSET
1,2
COMMENTS
Column 4 of A302367.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) -7*a(n-2) +10*a(n-3) -30*a(n-4) -21*a(n-5) -3*a(n-6) -68*a(n-7) +280*a(n-8) +414*a(n-9) +164*a(n-10) -423*a(n-11) -1527*a(n-12) +833*a(n-13) +1714*a(n-14) -2022*a(n-15) -1901*a(n-16) +367*a(n-17) +2024*a(n-18) +923*a(n-19) +66*a(n-20) -142*a(n-21) -5380*a(n-22) +4543*a(n-23) +13152*a(n-24) -11763*a(n-25) -12833*a(n-26) +16700*a(n-27) +4765*a(n-28) -15572*a(n-29) +1243*a(n-30) +9288*a(n-31) -3398*a(n-32) -4331*a(n-33) +2341*a(n-34) +1523*a(n-35) -1099*a(n-36) -619*a(n-37) +631*a(n-38) +476*a(n-39) -262*a(n-40) -191*a(n-41) +217*a(n-42) -15*a(n-43) -90*a(n-44) +18*a(n-45) +6*a(n-46) -14*a(n-47) +4*a(n-48) +6*a(n-49) -2*a(n-50) for n>53
EXAMPLE
Some solutions for n=5
..0..1..0..0. .0..1..1..1. .0..1..1..1. .0..1..1..1. .0..0..1..1
..0..1..0..0. .1..1..1..0. .0..1..1..0. .1..1..1..1. .0..0..1..1
..1..1..1..1. .0..1..1..0. .1..1..1..0. .1..0..0..0. .1..1..0..0
..0..0..1..1. .0..1..1..1. .0..1..1..0. .1..1..0..1. .1..1..0..0
..0..0..1..1. .0..1..1..0. .0..1..1..0. .1..1..0..1. .1..1..0..0
CROSSREFS
Cf. A302367.
Sequence in context: A040381 A354569 A022354 * A165841 A222958 A374170
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 06 2018
STATUS
approved