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A183731 1/16 the number of (n+1) X 3 0..7 arrays with every 2 X 2 subblock strictly increasing clockwise or counterclockwise with one decrease, and at least two adjacent blocks having the same increasing direction. 2
21, 290, 13169, 550268, 19849923, 667017027, 21320890377, 659741463420, 19939380387212, 592112324464323, 17343862233069362, 502495529472928971, 14428841233622907321, 411240107421964502725, 11647315145815312830954 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A183738.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n)=59*a(n-1)-983*a(n-2)+1517*a(n-3)+56964*a(n-4)-301681*a(n-5)-391561*a(n-6)+6287597*a(n-7)-12340851*a(n-8)-17981853*a(n-9)+86923852*a(n-10)-42259832*a(n-11)-195169753*a(n-12)+251286677*a(n-13)+147371126*a(n-14)-407605405*a(n-15)+42991424*a(n-16)+309052737*a(n-17)-122546216*a(n-18)-125908592*a(n-19)+73571657*a(n-20)+29253790*a(n-21)-21987805*a(n-22)-3922294*a(n-23)+3666493*a(n-24)+284823*a(n-25)-339999*a(n-26)-7395*a(n-27)+16089*a(n-28)-300*a(n-29)-300*a(n-30)+16*a(n-31).

EXAMPLE

Some solutions with the first block increasing clockwise for 3 X 3:

..7..0..6....6..7..0....3..5..4....6..1..7....0..2..0....0..1..2....0..2..7

..4..1..4....4..2..1....2..7..3....5..2..5....7..3..7....6..4..3....7..3..6

..3..2..3....6..7..0....1..0..1....4..3..4....6..4..5....7..1..2....5..4..5

...

...R..L.......R..R.......R..L.......R..L.......R..L.......R..R.......R..L...

...R..L.......L..L.......R..L.......R..L.......R..L.......L..L.......R..L...

CROSSREFS

Sequence in context: A317696 A025967 A022452 * A101703 A102018 A086947

Adjacent sequences:  A183728 A183729 A183730 * A183732 A183733 A183734

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 06 2011

STATUS

approved

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Last modified October 14 08:54 EDT 2019. Contains 327995 sequences. (Running on oeis4.)