A227267 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of three or less, with rows and columns of the latter in lexicographically nondecreasing order

5, 30, 132, 513, 1949, 7131, 24496, 78761, 238146, 681095, 1852355, 4813290, 11999195, 28801351, 66769946, 149914163, 326768708, 692941231, 1432287640, 2890510485, 5704099317, 11022017108, 20880164204, 38823463828, 70923212058

Offset

1,1

Comments

Column 4 of A227269

Links

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

Formula

Empirical: a(n) = (1/121645100408832000)*n^19 + (1/6402373705728000)*n^18 + (23/1067062284288000)*n^17 + (31/62768369664000)*n^16 + (37/5706215424000)*n^15 + (4111/5706215424000)*n^14 - (301079/47076277248000)*n^13 + (126941/452656512000)*n^12 + (14792293/9656672256000)*n^11 - (78942259/877879296000)*n^10 + (13084929349/4828336128000)*n^9 - (165214115519/4828336128000)*n^8 + (5087156753417/23538138624000)*n^7 + (3282017247319/2942267328000)*n^6 - (4087118559803/118879488000)*n^5 + (37821361216913/118879488000)*n^4 - (460675235565641/308756448000)*n^3 + (19317471160409/6175128960)*n^2 + (109108917509/232792560)*n - 9102 for n>7

Example

Some solutions for n=4
..1..1..1..1....1..1..1..0....1..1..1..1....1..1..1..1....1..1..1..0
..1..1..1..0....1..1..1..1....1..1..1..1....1..1..0..0....1..1..0..0
..1..0..1..1....0..1..1..1....1..1..0..1....1..0..0..0....1..1..0..0
..0..0..1..1....0..1..1..0....1..1..1..1....1..1..1..1....1..0..0..0

Crossrefs

Sequence in context: A027173 A286973 A196452 * A213260 A054612 A358543

Adjacent sequences: A227264 A227265 A227266 * A227268 A227269 A227270

Keyword

nonn

Author

R. H. Hardin Jul 04 2013

Status

approved