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A297981 Number of n X 3 0..1 arrays with every element equal to 0, 2, 3 or 6 king-move adjacent elements, with upper left element zero. 2
1, 6, 2, 5, 7, 14, 21, 41, 70, 129, 233, 428, 783, 1445, 2664, 4933, 9137, 16956, 31495, 58557, 108952, 202837, 377797, 703972, 1312155, 2446433, 4562176, 8509137, 15873089, 29613308, 55252631, 103098397, 192387744, 359025085, 670023141 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A297986.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 2*a(n-2) + a(n-3) - a(n-4) - 4*a(n-6) - 8*a(n-7) - 2*a(n-8) + 4*a(n-9) + 6*a(n-10) + 2*a(n-11) for n>13.

Empirical g.f.: x*(1 + 5*x - 6*x^2 - 10*x^3 - 7*x^4 + x^5 - 6*x^6 + 22*x^7 + 38*x^8 + 14*x^9 - 14*x^10 - 16*x^11 - 4*x^12) / ((1 - x)*(1 + x)*(1 - x - x^2 - 2*x^3 - 2*x^5 + 4*x^6 + 6*x^7 + 6*x^8 + 2*x^9)). - Colin Barker, Mar 22 2018

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Cf. A297986.

Sequence in context: A270614 A011489 A093601 * A193780 A220260 A238901

Adjacent sequences:  A297978 A297979 A297980 * A297982 A297983 A297984

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 10 2018

STATUS

approved

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Last modified September 18 16:10 EDT 2021. Contains 347527 sequences. (Running on oeis4.)