A227123 Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order

5, 23, 81, 295, 1079, 3836, 12954, 41334, 124956, 359214, 985377, 2587934, 6528298, 15865511, 37249628, 84702904, 186968944, 401441143, 839947739, 1715449948, 3424892827, 6693385156, 12820586861, 24094606746, 44476144089, 80712174607

Offset

1,1

Comments

Column 4 of A227125

Links

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

Formula

Empirical: a(n) = (1/121645100408832000)*n^19 + (1/43553562624000)*n^17 + (107/8966909952000)*n^15 + (1/2905943040)*n^14 - (1275569/188305108992000)*n^13 + (23/68428800)*n^12 - (5672753/1379524608000)*n^11 + (191/6220800)*n^10 + (1099466111/1379524608000)*n^9 - (2116283/101606400)*n^8 + (12673870051501/47076277248000)*n^7 - (2627953/1555200)*n^6 + (133732420531/124540416000)*n^5 + (312421343/4276800)*n^4 - (1712634732923/2940537600)*n^3 + (154276843207/75675600)*n^2 - (88924473629/29099070)*n + 944 for n>6

Example

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

Crossrefs

Sequence in context: A211809 A211922 A139209 * A113946 A283114 A290938

Adjacent sequences: A227120 A227121 A227122 * A227124 A227125 A227126

Keyword

nonn

Author

R. H. Hardin Jul 01 2013

Status

approved