A302273 Number of n X 3 0..1 arrays with every element equal to 1, 2 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

1, 7, 22, 79, 269, 942, 3401, 12283, 43006, 156939, 565249, 2007662, 7307653, 26305407, 94096702, 341521831, 1229036517, 4413205998, 15980067713, 57514505187, 206942767678, 748087603299, 2693270343273, 9700931065070

Offset: 1

Author

R. H. Hardin, Apr 04 2018

Keywords

• nonn

Comments

Column 3 of A302278.

Examples

			Some solutions for n=5:
  0 0 1    0 1 0    0 0 0    0 1 1    0 0 1    0 1 0    0 1 1
  1 1 0    0 0 1    0 1 0    0 0 1    1 1 0    1 0 1    0 0 1
  1 1 1    0 1 1    0 0 1    1 1 1    0 0 0    0 1 0    1 1 1
  1 0 0    0 0 0    1 0 0    1 1 0    1 0 0    1 0 1    0 1 1
  0 1 1    0 1 1    0 1 0    0 0 1    0 1 1    1 1 1    1 0 0
		

Links

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

Crossrefs

Cf. A302278.

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) +26*a(n-3) -66*a(n-4) -86*a(n-5) +79*a(n-6) +14*a(n-7) +13*a(n-8) -168*a(n-9) +250*a(n-10) +428*a(n-11) -232*a(n-12) -24*a(n-13) -160*a(n-14) +160*a(n-15) -256*a(n-16) -384*a(n-17) +256*a(n-18).