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A301537
Number of nX4 0..1 arrays with every element equal to 0, 1 or 3 horizontally or vertically adjacent elements, with upper left element zero.
1
5, 10, 26, 79, 212, 603, 1841, 5663, 17379, 53565, 166423, 518704, 1616890, 5041039, 15729206, 49104949, 153322792, 478742546, 1494954997, 4668557664, 14579783689, 45532767521, 142200230227, 444098944427, 1386951488437, 4331554392329
OFFSET
1,1
COMMENTS
Column 4 of A301541.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +2*a(n-2) -a(n-3) +4*a(n-4) -34*a(n-5) -75*a(n-6) -14*a(n-7) +46*a(n-8) +323*a(n-9) +751*a(n-10) +478*a(n-11) -191*a(n-12) -1729*a(n-13) -4244*a(n-14) -4352*a(n-15) -1713*a(n-16) +4203*a(n-17) +13644*a(n-18) +18309*a(n-19) +13580*a(n-20) -167*a(n-21) -21556*a(n-22) -37473*a(n-23) -38916*a(n-24) -23118*a(n-25) +7056*a(n-26) +36004*a(n-27) +52920*a(n-28) +52093*a(n-29) +29895*a(n-30) -29895*a(n-32) -52093*a(n-33) -52920*a(n-34) -36004*a(n-35) -7056*a(n-36) +23118*a(n-37) +38916*a(n-38) +37473*a(n-39) +21556*a(n-40) +167*a(n-41) -13580*a(n-42) -18309*a(n-43) -13644*a(n-44) -4203*a(n-45) +1713*a(n-46) +4352*a(n-47) +4244*a(n-48) +1729*a(n-49) +191*a(n-50) -478*a(n-51) -751*a(n-52) -323*a(n-53) -46*a(n-54) +14*a(n-55) +75*a(n-56) +34*a(n-57) -4*a(n-58) +a(n-59) -2*a(n-60) -3*a(n-61) +a(n-62)
EXAMPLE
Some solutions for n=5
..0..1..0..1. .0..1..1..1. .0..0..0..1. .0..1..1..0. .0..1..1..0
..1..1..0..0. .0..0..1..0. .1..0..1..0. .1..0..0..0. .0..0..0..0
..0..1..0..1. .0..1..0..1. .0..1..0..1. .1..1..0..0. .0..0..0..0
..1..0..1..0. .1..0..1..0. .1..0..1..0. .1..0..0..0. .0..1..1..0
..1..0..1..0. .1..0..1..0. .0..1..0..1. .0..1..1..0. .1..0..0..1
CROSSREFS
Cf. A301541.
Sequence in context: A166388 A290055 A066872 * A063478 A128665 A218466
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 23 2018
STATUS
approved