A303626 Number of 4Xn 0..1 arrays with every element equal to 0, 2, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

8, 3, 148, 325, 3591, 19467, 160807, 1173612, 9421103, 75073653, 610163560, 4982200456, 40884018586, 336380001790, 2772144413449, 22869613342371, 188783964530800, 1558985724471489, 12877140629903061, 106380021298938000

Offset: 1

Author

R. H. Hardin, Apr 27 2018

Keywords

• nonn

Comments

Row 4 of A303624.

Examples

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

Links

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

Crossrefs

Cf. A303624.

Formula

Empirical: a(n) = 16*a(n-1) -39*a(n-2) -486*a(n-3) +2076*a(n-4) +6509*a(n-5) -36557*a(n-6) -51456*a(n-7) +351943*a(n-8) +315012*a(n-9) -2226007*a(n-10) -1747803*a(n-11) [phone]*a(n-12) +7461453*a(n-13) -38373678*a(n-14) -20050380*a(n-15) [phone]*a(n-16) [phone]*a(n-17) -222622519*a(n-18) -3530085*a(n-19) [phone]*a(n-20) -76201625*a(n-21) -361639017*a(n-22) [phone]*a(n-23) [phone]*a(n-24) -255187688*a(n-25) [phone]*a(n-26) [phone]*a(n-27) -306102478*a(n-28) -223408872*a(n-29) [phone]*a(n-30) [phone]*a(n-31) -344439874*a(n-32) -146637084*a(n-33) [phone]*a(n-34) [phone]*a(n-35) -61685576*a(n-36) -35202400*a(n-37) +8565840*a(n-38) +7517168*a(n-39) +603968*a(n-40) -519744*a(n-41) -231936*a(n-42) -40960*a(n-43) for n>44