A302624 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 25, 25, 45, 79, 146, 286, 563, 1114, 2222, 4435, 8858, 17710, 35411, 70810, 141614, 283219, 566426, 1132846, 2265683, 4531354, 9062702, 18125395, 36250778, 72501550, 145003091, 290006170, 580012334, 1160024659, 2320049306, 4640098606

Offset

1,1

Comments

Row 3 of A302623.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-3) -2*a(n-4) for n>8

Example

Some solutions for n=5
..0..1..0..1..1. .0..0..1..0..1. .0..1..1..0..1. .0..1..0..1..1
..0..1..0..1..0. .1..0..0..0..1. .0..0..1..0..1. .1..0..1..0..0
..1..1..0..1..1. .1..0..1..0..1. .1..0..1..0..0. .1..0..1..0..1

Crossrefs

Cf. A302623.

Sequence in context: A114392 A281471 A107734 * A238515 A043067 A289273

Adjacent sequences: A302621 A302622 A302623 * A302625 A302626 A302627

Keyword

nonn

Author

R. H. Hardin, Apr 10 2018

Status

approved