A266013 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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