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A302878 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 6, 17, 35, 72, 241, 722, 1821, 4863, 14841, 43444, 119306, 335624, 985356, 2849009, 8044468, 22928355, 66336411, 190801483, 543986757, 1556622000, 4478561650, 12855871827, 36783013974, 105393294206, 302583744944, 867943015259 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A302877.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-2) +2*a(n-3) +36*a(n-4) -22*a(n-5) -100*a(n-6) -5*a(n-7) -280*a(n-8) +97*a(n-9) +725*a(n-10) -111*a(n-11) +481*a(n-12) -72*a(n-13) -1160*a(n-14) +511*a(n-15) +19*a(n-16) +9*a(n-17) +24*a(n-18) -10*a(n-19) -a(n-20) for n>21

EXAMPLE

Some solutions for n=5

..0..1..1..1..0. .0..1..0..0..0. .0..1..0..1..0. .0..1..0..1..1

..0..1..0..1..0. .1..1..0..1..0. .0..1..0..1..0. .0..1..0..0..0

..0..1..0..1..0. .0..1..0..1..0. .0..1..0..0..0. .0..1..1..1..0

CROSSREFS

Cf. A302877.

Sequence in context: A320245 A034492 A125691 * A270270 A211949 A079803

Adjacent sequences:  A302875 A302876 A302877 * A302879 A302880 A302881

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 15 2018

STATUS

approved

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Last modified June 3 22:20 EDT 2020. Contains 334804 sequences. (Running on oeis4.)