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A301536 Number of nX3 0..1 arrays with every element equal to 0, 1 or 3 horizontally or vertically adjacent elements, with upper left element zero. 1
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 (list; graph; refs; listen; history; text; internal format)
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: A061929 A318032 A326160 * A296110 A019461 A223556

Adjacent sequences:  A301533 A301534 A301535 * A301537 A301538 A301539

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 23 2018

STATUS

approved

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Last modified June 7 01:26 EDT 2020. Contains 334836 sequences. (Running on oeis4.)