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A301907 Number of 3Xn 0..1 arrays with every element equal to 0, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. 1
4, 1, 3, 2, 2, 7, 12, 27, 62, 160, 387, 951, 2362, 5895, 14745, 36892, 92334, 231171, 578926, 1450251, 3633632, 9105130, 22816655, 57178265, 143291478, 359102513, 899959089, 2255439374, 5652518690, 14166233267, 35503222896, 88977846175 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A301906.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +a(n-2) +3*a(n-4) -a(n-6) -4*a(n-7) -17*a(n-8) -30*a(n-9) -27*a(n-10) -36*a(n-11) -6*a(n-12) +4*a(n-13) +22*a(n-14) +36*a(n-15) +46*a(n-16) +32*a(n-17) +22*a(n-18) -4*a(n-19) -11*a(n-20) -6*a(n-21) -19*a(n-22) -4*a(n-23) -9*a(n-24) +4*a(n-25) -a(n-26) +4*a(n-27) -a(n-28) +2*a(n-29) -a(n-30) for n>31

EXAMPLE

All solutions for n=5

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

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

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

CROSSREFS

Cf. A301906.

Sequence in context: A123251 A327357 A021246 * A197840 A019633 A067277

Adjacent sequences:  A301904 A301905 A301906 * A301908 A301909 A301910

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 28 2018

STATUS

approved

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Last modified February 25 08:21 EST 2020. Contains 332221 sequences. (Running on oeis4.)