A222098 Number of n X 2 0..5 arrays with entries increasing mod 6 by 0, 1, 2 or 3 rightwards and downwards, starting with upper left zero.

4, 46, 530, 6108, 70394, 811286, 9350020, 107758398, 1241908834, 14312922076, 164955536810, 1901102303238, 21910085816324, 252512376457166, 2910189435065650, 33539752256081628, 386543558932945114

Offset

1,1

Comments

Column 2 of A222104.

Links

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

Formula

Empirical: a(n) = 13*a(n-1) - 17*a(n-2).

Conjectures from Colin Barker, Aug 15 2018: (Start)

G.f.: 2*x*(2 - 3*x) / (1 - 13*x + 17*x^2).

a(n) = (2^(-n)*((13-sqrt(101))^n*(-29+3*sqrt(101)) + (13+sqrt(101))^n*(29+3*sqrt(101)))) / (17*sqrt(101)).

(End)

Example

Some solutions for n=3:
..0..1....0..3....0..3....0..0....0..0....0..3....0..3....0..0....0..2....0..2
..0..1....3..0....3..3....3..0....0..1....2..4....3..0....3..3....2..3....1..3
..0..1....5..0....0..0....0..2....2..3....2..4....4..1....3..0....4..5....4..4

Crossrefs

Cf. A222104.

Sequence in context: A097952 A097643 A155652 * A197131 A235132 A236956

Adjacent sequences: A222095 A222096 A222097 * A222099 A222100 A222101

Keyword

nonn

Author

R. H. Hardin, Feb 07 2013

Status

approved