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A253327 Number of (2+1)X(n+1) 0..1 arrays with every 2X2 subblock sum nondecreasing horizontally, vertically and antidiagonally ne-to-sw 1
44, 126, 373, 1026, 2797, 6936, 17197, 39616, 91571, 200800, 442031, 937998, 1997242, 4147312, 8635487, 17680582, 36274902, 73603454, 149571217, 301772250, 609502075, 1225424712, 2465561705, 4946547564, 9928863677, 19894339804 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A253326

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) +8*a(n-2) -50*a(n-3) -9*a(n-4) +270*a(n-5) -128*a(n-6) -820*a(n-7) +709*a(n-8) +1520*a(n-9) -1824*a(n-10) -1722*a(n-11) +2797*a(n-12) +1070*a(n-13) -2696*a(n-14) -160*a(n-15) +1608*a(n-16) -240*a(n-17) -544*a(n-18) +160*a(n-19) +80*a(n-20) -32*a(n-21)

EXAMPLE

Some solutions for n=4

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

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

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

CROSSREFS

Sequence in context: A039441 A044295 A044676 * A253320 A230829 A183642

Adjacent sequences:  A253324 A253325 A253326 * A253328 A253329 A253330

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 30 2014

STATUS

approved

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Last modified June 27 04:37 EDT 2022. Contains 354888 sequences. (Running on oeis4.)