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.

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

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: A285595 A255566 A371210 * A303243 A074676 A257505

Adjacent sequences: A302458 A302459 A302460 * A302462 A302463 A302464

Keyword

nonn

Author

R. H. Hardin, Apr 08 2018

Status

approved