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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. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 25 13:19 EDT 2022. Contains 354851 sequences. (Running on oeis4.)