A210119 Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having two or four distinct values, and new values 0..3 introduced in row major order.

44, 481, 5587, 67585, 836053, 10466659, 131849767, 1666227265, 21090849853, 267184911211, 3386189676751, 42924236694073, 544177325000245, 6899249896382995, 87473246343061879, 1109059012082436337

Offset

1,1

Comments

Column 2 of A210125.

Links

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

Formula

Empirical: a(n) = 24*a(n-1) - 174*a(n-2) + 368*a(n-3) + 303*a(n-4) - 888*a(n-5) - 340*a(n-6) + 240*a(n-7).

Empirical g.f.: x*(44 - 575*x + 1699*x^2 + 999*x^3 - 4189*x^4 - 1510*x^5 + 1120*x^6) / ((1 - 6*x - 3*x^2 + 2*x^3)*(1 - 18*x + 69*x^2 - 10*x^3 - 120*x^4)). - Colin Barker, Jul 14 2018

Example

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

Crossrefs

Cf. A210125.

Sequence in context: A221730 A306036 A160150 * A272186 A222514 A282645

Adjacent sequences: A210116 A210117 A210118 * A210120 A210121 A210122

Keyword

nonn

Author

R. H. Hardin, Mar 17 2012

Status

approved