A251231 Number of (n+1) X (3+1) 0..3 arrays with every 2 X 2 subblock summing to 6 and no 2 X 2 subblock having exactly two nonzero entries.

322, 694, 1592, 3886, 9914, 26224, 71322, 198318, 561212, 1611002, 4679574, 13730612, 40642206, 121238834, 364209520, 1101127798, 3348686298, 10239114144, 31464490330, 97136312190, 301153069996, 937321265322, 2927816428982

Offset

1,1

Comments

Column 3 of A251236.

Links

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

Formula

Empirical: a(n) = 13*a(n-1) -63*a(n-2) +122*a(n-3) +13*a(n-4) -371*a(n-5) +317*a(n-6) +308*a(n-7) -370*a(n-8) -144*a(n-9) +128*a(n-10) +48*a(n-11).

Example

Some solutions for n=4:
..1..1..0..1....0..2..1..2....3..1..1..2....1..3..1..3....0..1..1..3
..1..3..2..3....2..2..1..2....1..1..3..0....1..1..1..1....3..2..2..0
..2..0..1..0....1..1..2..1....3..1..1..2....1..3..1..3....1..0..2..2
..1..3..2..3....3..1..2..1....0..2..2..1....1..1..1..1....3..2..2..0
..1..1..0..1....1..1..2..1....3..1..1..2....3..1..3..1....0..1..1..3

Crossrefs

Cf. A251236.

Sequence in context: A379372 A004947 A004967 * A252274 A114358 A158305

Adjacent sequences: A251228 A251229 A251230 * A251232 A251233 A251234

Keyword

nonn

Author

R. H. Hardin, Nov 30 2014

Status

approved