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A302461 Number of 3Xn 0..1 arrays with every element equal to 0, 2, 3 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. 1
4, 2, 18, 8, 44, 56, 140, 364, 764, 2352, 5612, 16144, 42324, 116260, 314408, 853216, 2319700, 6290064, 17095288, 46394920, 126019004, 342168972, 929215108, 2523394628, 6852508984, 18609263140, 50535852808, 137239321084, 372695225548 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A302460.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +10*a(n-2) -15*a(n-3) -46*a(n-4) +49*a(n-5) +121*a(n-6) -95*a(n-7) -193*a(n-8) +123*a(n-9) +187*a(n-10) -126*a(n-11) -96*a(n-12) +78*a(n-13) +20*a(n-14) -24*a(n-15) +6*a(n-16) +20*a(n-17) -4*a(n-19) for n>20

EXAMPLE

Some solutions for n=5

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

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

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

CROSSREFS

Cf. A302460.

Sequence in context: A328695 A285595 A255566 * A303243 A074676 A257505

Adjacent sequences:  A302458 A302459 A302460 * A302462 A302463 A302464

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 08 2018

STATUS

approved

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Last modified July 23 22:20 EDT 2021. Contains 346265 sequences. (Running on oeis4.)