A301536 Number of n X 3 0..1 arrays with every element equal to 0, 1 or 3 horizontally or vertically adjacent elements, with upper left element zero.

3, 6, 9, 26, 61, 154, 374, 941, 2357, 5963, 15074, 38168, 96641, 244836, 620311, 1571854, 3983147, 10093850, 25579490, 64823479, 164276135, 416311227, 1055023990, 2673664936, 6775663297, 17171047596, 43515284891, 110277499816

Offset

1,1

Comments

Column 3 of A301541.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -a(n-2) -a(n-3) +2*a(n-4) -a(n-5) +3*a(n-6) -11*a(n-7) -a(n-8) +2*a(n-9) -4*a(n-10) -2*a(n-11) -a(n-12) +11*a(n-13) +3*a(n-14) +a(n-15) +2*a(n-16) +a(n-17) -a(n-18) -3*a(n-19) -a(n-20).

Example

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

Crossrefs

Cf. A301541.

Sequence in context: A358403 A318032 A326160 * A296110 A019461 A223556

Adjacent sequences: A301533 A301534 A301535 * A301537 A301538 A301539

Keyword

nonn

Author

R. H. Hardin, Mar 23 2018

Status

approved