login
A304672
Number of nX4 0..1 arrays with every element unequal to 0, 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero.
1
1, 13, 23, 56, 199, 598, 1950, 6588, 21871, 72947, 246313, 831539, 2800595, 9456853, 31947922, 107896991, 364471611, 1231447079, 4160781508, 14058449969, 47502997786, 160513512708, 542381014412, 1832740869231, 6192990940151
OFFSET
1,2
COMMENTS
Column 4 of A304676.
FORMULA
Empirical recurrence of order 70 (see link above)
EXAMPLE
Some solutions for n=5
..0..1..1..0. .0..1..0..1. .0..0..1..0. .0..1..1..0. .0..0..0..1
..0..1..0..1. .1..0..1..0. .1..1..0..1. .0..1..0..1. .1..1..0..0
..0..1..0..1. .1..1..0..0. .1..1..1..0. .0..0..1..1. .0..1..1..1
..0..0..1..0. .1..0..1..0. .1..1..0..1. .0..1..0..1. .1..1..0..1
..1..0..0..1. .0..1..0..1. .0..0..1..0. .1..0..0..1. .0..0..0..1
CROSSREFS
Cf. A304676.
Sequence in context: A154863 A194156 A139863 * A316119 A046862 A155093
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 16 2018
STATUS
approved