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A235549 Number of (n+1) X (1+1) 0..1 arrays with the sum of each 2 X 2 subblock two extreme terms minus its two median terms lexicographically nondecreasing rowwise and columnwise. 2
16, 46, 120, 288, 660, 1456, 3136, 6624, 13808, 28480, 58304, 118656, 240448, 485632, 978432, 1967616, 3951360, 7926784, 15889408, 31832064, 63742976, 127602688, 255377408, 511008768, 1022390272, 2045329408, 4091461632, 8184102912 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A235555.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 4*a(n-2) - 8*a(n-3) - 4*a(n-4) + 8*a(n-5).

Empirical g.f.: 2*x*(8 + 7*x - 18*x^2 - 4*x^3 + 18*x^4) / ((1 - 2*x)*(1 - 2*x^2)^2). - Colin Barker, Mar 19 2018

EXAMPLE

Some solutions for n=5:

..0..1....0..0....1..0....1..1....1..0....1..1....0..0....1..1....0..1....0..0

..1..1....1..1....1..0....1..0....1..0....1..0....1..1....1..0....1..0....0..0

..0..1....0..0....0..1....1..0....0..1....1..1....0..0....1..1....1..0....0..0

..1..1....0..0....0..1....1..0....0..1....1..0....0..0....0..1....0..0....0..0

..0..0....0..0....0..0....1..0....0..1....1..1....1..1....0..1....1..0....0..0

..0..0....1..1....1..0....0..0....1..0....0..0....1..1....0..1....0..0....1..1

CROSSREFS

Cf. A235555.

Sequence in context: A099003 A124709 A244094 * A126370 A133345 A253231

Adjacent sequences:  A235546 A235547 A235548 * A235550 A235551 A235552

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 12 2014

STATUS

approved

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Last modified January 27 16:30 EST 2022. Contains 350608 sequences. (Running on oeis4.)