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A301664 Number of nX3 0..1 arrays with every element equal to 1, 2 or 4 horizontally or vertically adjacent elements, with upper left element zero. 1
1, 10, 30, 118, 407, 1498, 5289, 19184, 68832, 247756, 890523, 3203084, 11517675, 41422044, 148957388, 535680672, 1926390947, 6927645818, 24912983963, 89591402294, 322185988646, 1158636174394, 4166654317703, 14984004032116 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A301669.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +6*a(n-2) -2*a(n-4) +2*a(n-5) -9*a(n-6) -50*a(n-7) -37*a(n-8) +34*a(n-9) +43*a(n-10) -16*a(n-11) +15*a(n-12) +18*a(n-13) -7*a(n-14) -2*a(n-16) +4*a(n-17) -6*a(n-18) +a(n-20)

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A301669.

Sequence in context: A245428 A307307 A185829 * A259136 A098684 A268117

Adjacent sequences:  A301661 A301662 A301663 * A301665 A301666 A301667

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 25 2018

STATUS

approved

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Last modified April 23 14:15 EDT 2019. Contains 322386 sequences. (Running on oeis4.)