A266013 - OEIS

A266013

Number of 3Xn integer arrays with each element equal to the number of horizontal and antidiagonal neighbors equal to itself.

1, 2, 6, 4, 11, 18, 27, 43, 62, 112, 191, 310, 548, 883, 1467, 2535, 4210, 6993, 11848, 19780, 33042, 55676, 93207, 155834, 261837, 438753, 734590, 1232614, 2065881, 3460646, 5803604, 9727967, 16300819, 27328897, 45809212, 76772793, 128697166

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OFFSET

1,2

COMMENTS

Row 3 of A266012.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-3) +2*a(n-4) +2*a(n-5) +a(n-6) -2*a(n-7) -2*a(n-8) -3*a(n-9) +2*a(n-10) +2*a(n-11) +5*a(n-12) -a(n-15) for n>19

EXAMPLE

All solutions for n=4

..0..1..1..0....1..1..2..2....0..1..2..2....0..1..1..0

..0..2..2..1....0..2..2..0....1..2..2..0....0..2..2..0

..2..2..1..0....0..1..1..0....0..1..1..0....2..2..1..1

CROSSREFS

Cf. A266012.

Sequence in context: A090546 A242901 A353731 * A222423 A059909 A145177

Adjacent sequences: A266010 A266011 A266012 * A266014 A266015 A266016

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 20 2015

STATUS

approved