login
A303804
Number of nX4 0..1 arrays with every element unequal to 0, 1, 3 or 4 king-move adjacent elements, with upper left element zero.
1
5, 17, 15, 38, 55, 107, 202, 438, 853, 1858, 3939, 8667, 18603, 41667, 92140, 205636, 455688, 1021747, 2281353, 5111090, 11431713, 25646573, 57451732, 128832642, 288776875, 647818224, 1452633630, 3258392662, 7307981425, 16393919986
OFFSET
1,1
COMMENTS
Column 4 of A303808.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) -4*a(n-2) -a(n-3) +9*a(n-4) -25*a(n-5) +34*a(n-6) -21*a(n-7) -17*a(n-8) +20*a(n-9) -9*a(n-10) +80*a(n-11) -82*a(n-12) +5*a(n-13) +115*a(n-14) -65*a(n-15) -48*a(n-16) +9*a(n-17) -5*a(n-18) +2*a(n-20) for n>24
EXAMPLE
Some solutions for n=5
..0..0..1..1. .0..1..1..1. .0..1..1..1. .0..1..0..1. .0..1..1..1
..0..0..0..1. .1..1..1..1. .0..0..1..1. .1..1..0..0. .1..1..1..1
..0..0..0..0. .1..1..1..1. .0..0..1..0. .1..1..0..0. .1..1..1..1
..1..0..0..0. .1..1..1..1. .0..1..1..0. .1..1..0..0. .0..1..1..1
..1..1..0..0. .0..1..1..0. .1..1..1..1. .1..0..1..0. .0..0..1..1
CROSSREFS
Cf. A303808.
Sequence in context: A056850 A302631 A303678 * A304851 A237437 A128895
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 30 2018
STATUS
approved