A214113 Number of 0..3 colorings of a 2X(n+1) array circular in the n+1 direction with new values 0..3 introduced in row major order

4, 11, 111, 670, 4994, 34041, 241021, 1678940, 11777184, 82366471, 576786731, 4036842810, 28259892574, 197813269301, 1384710821241, 9692921940280, 67850615007164, 474953820774531, 3324678198248551, 23272743029259350

Offset

1,1

Comments

Row 2 of A214112

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +22*a(n-2) -4*a(n-3) -21*a(n-4).

Empirical: G.f. -x*(7*x+4)*(3*x-1) / ( (x-1)*(3*x+1)*(7*x-1)*(1+x) ), a(n) = 11/24 +3*(-1)^(n+1)/8 +7^(n+1)/24 +(-3)^(n+1)/8. - R. J. Mathar, Jul 04 2012

Example

Some solutions for n=4
..0..1..0..2..3....0..1..2..0..1....0..1..2..3..1....0..1..2..0..3
..1..2..1..3..0....1..2..3..1..0....3..2..0..1..2....3..0..1..2..0

Crossrefs

Sequence in context: A144744 A267154 A320501 * A167418 A055979 A018242

Adjacent sequences: A214110 A214111 A214112 * A214114 A214115 A214116

Keyword

nonn

Author

R. H. Hardin Jul 04 2012

Status

approved