A227330 Number of n X 3 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 4 binary array having two adjacent 1's and two adjacent 0's, with rows and columns of the latter in lexicographically nondecreasing order.

8, 34, 153, 708, 3013, 11292, 37312, 110816, 301923, 766340, 1832683, 4164473, 9050350, 18908103, 38136118, 74516301, 141474093, 261645212, 472399946, 834253036, 1443464344, 2450642643, 4087839408, 6707507638, 10837859135

Offset

1,1

Comments

Column 3 of A227333.

Links

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

Formula

Empirical: a(n) = (1/1307674368000)*n^15 + (1/87178291200)*n^14 + (19/7472424960)*n^13 - (1/191600640)*n^12 + (36577/14370048000)*n^11 - (2689/87091200)*n^10 + (436297/365783040)*n^9 - (2115367/121927680)*n^8 + (6669593/23328000)*n^7 - (13770361/4354560)*n^6 + (104682953/3592512)*n^5 - (2364431063/11975040)*n^4 + (366060925289/378378000)*n^3 - (487180400717/151351200)*n^2 + (2320943983/360360)*n - 5585 for n>6.

Example

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

Crossrefs

Sequence in context: A101644 A126395 A335749 * A252934 A229398 A223015

Adjacent sequences: A227327 A227328 A227329 * A227331 A227332 A227333

Keyword

nonn

Author

R. H. Hardin Jul 07 2013

Status

approved