login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A302310
Number of 2Xn 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
4
2, 3, 11, 21, 31, 113, 363, 813, 1751, 5001, 14051, 34053, 82063, 218273, 579291, 1452381, 3638471, 9447993, 24526163, 62318133, 158325631, 407598161, 1049289291, 2679681933, 6843284663, 17562012393, 45069368771, 115317418341
OFFSET
1,1
COMMENTS
Row 2 of A302309.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +4*a(n-3) +12*a(n-4) -16*a(n-5) for n>6
EXAMPLE
Some solutions for n=5
..0..1..0..0..1. .0..1..0..1..0. .0..1..0..1..1. .0..1..0..1..0
..0..0..1..0..1. .1..0..0..1..0. .0..1..0..0..0. .0..1..1..1..0
CROSSREFS
Cf. A302309.
Sequence in context: A298351 A359017 A023182 * A295958 A049083 A305719
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 05 2018
STATUS
approved