A183649 Number of (n+1) X 7 0..4 arrays with every 2 X 2 subblock summing to 8.

115525, 205001, 431125, 1037585, 2764525, 7969001, 24478885, 79273025, 268445725, 944464601, 3434578645, 12856134065, 49365995725, 193928921801, 777715558405, 3178692764705, 13225029670525, 55959955612601, 240655091866165, 1051225876268945, 4661480350286125, 20969377163929001

Offset

1,1

Links

Table of n, a(n) for n=1..22.

Christian Krause, Proof of formulas, Jun 12 2026.

Index entries for linear recurrences with constant coefficients, signature (15,-85,225,-274,120).

Formula

a(n) = 15*a(n-1)-85*a(n-2)+225*a(n-3)-274*a(n-4)+120*a(n-5).

a(n) = 5*5^n + 504*4^n + 5796*3^n + 24276*2^n + 47544. - Christian Krause, Jun 12 2026

Example

Some solutions for 3 X 7
..0..3..1..3..2..1..1....0..4..1..4..3..0..4....0..1..3..0..3..3..1
..3..2..2..2..1..4..2....4..0..3..0..1..4..0....4..3..1..4..1..1..3
..1..2..2..2..3..0..2....0..4..1..4..3..0..4....0..1..3..0..3..3..1

Crossrefs

Column 6 of A183652.

Sequence in context: A186791 A069245 A215995 * A237166 A237382 A255080

Adjacent sequences: A183646 A183647 A183648 * A183650 A183651 A183652

Keyword

nonn,easy,changed

Author

R. H. Hardin, Jan 06 2011

Extensions

a(18)-a(22) from Christian Krause, Jun 12 2026

Status

approved