A278267 Number of n X 2 0..3 arrays with every element plus 1 mod 4 equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) (1,-1) or (1,0), with upper left element zero.

0, 4, 47, 395, 3453, 30475, 268257, 2360984, 20781746, 182923358, 1610107387, 14172312272, 124745996060, 1098025707095, 9664923050975, 85071539806558, 748807501780793, 6591072360831728, 58015223889383283, 510655325670196475

Offset

1,2

Links

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

Formula

Empirical: a(n) = 10*a(n-1) - 14*a(n-2) + 37*a(n-3) - 65*a(n-4) + 70*a(n-5) - 76*a(n-6) + 74*a(n-7) - 32*a(n-8).

Empirical g.f.: x^2*(4 + 7*x - 19*x^2 + 13*x^3 - 4*x^4 + 9*x^5 - 8*x^6) / (1 - 10*x + 14*x^2 - 37*x^3 + 65*x^4 - 70*x^5 + 76*x^6 - 74*x^7 + 32*x^8). - Colin Barker, Feb 09 2019

Example

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

Crossrefs

Column 2 of A278272.

Sequence in context: A186677 A277654 A247767 * A309329 A354405 A326434

Adjacent sequences: A278264 A278265 A278266 * A278268 A278269 A278270

Keyword

nonn

Author

R. H. Hardin, Nov 16 2016

Status

approved