A205636 Number of (n+1)X3 0..3 arrays with every 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward and upward neighbors.

2320, 28724, 377568, 5079336, 69574220, 962953968, 13444055224, 188823193784, 2664428266336, 37723583696052, 535447018219820, 7614062720813020, 108418400331562368, 1545312836738950012, 22041527502028941280

Offset

1,1

Comments

Column 2 of A205642.

Links

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

Formula

Empirical: a(n) = 40*a(n-1) -538*a(n-2) +1600*a(n-3) +26601*a(n-4) -244741*a(n-5) +233209*a(n-6) +5541744*a(n-7) -21842748*a(n-8) -32944767*a(n-9) +354353234*a(n-10) -303682333*a(n-11) -2646718872*a(n-12) +5934353280*a(n-13) +9289012973*a(n-14) -41577894950*a(n-15) -1914076326*a(n-16) +162268698987*a(n-17) -118745894358*a(n-18) -375952312601*a(n-19) +516190082301*a(n-20) +490860223665*a(n-21) -1126227747881*a(n-22) -278402542035*a(n-23) +1492073391103*a(n-24) -58128143145*a(n-25) -1376232661944*a(n-26) +209754887441*a(n-27) +989829393787*a(n-28) -250378408153*a(n-29) -438696247203*a(n-30) +73070040366*a(n-31) +159024306012*a(n-32) +15073020296*a(n-33) -63596130670*a(n-34) -2882562568*a(n-35) +13670636368*a(n-36) -797920044*a(n-37) -999511826*a(n-38) +247638480*a(n-39) -138158645*a(n-40) +29008218*a(n-41) +1133604*a(n-42) -336960*a(n-43) for n>45.

Example

Some solutions for n=4:
..0..1..0....3..0..2....2..3..0....1..2..1....1..0..0....2..1..2....1..1..1
..3..2..2....0..3..1....3..3..0....1..1..1....1..0..1....1..1..1....0..3..3
..1..1..0....1..0..2....0..3..3....2..1..3....1..1..1....2..1..3....3..3..0
..3..2..3....2..1..3....3..3..1....1..1..1....3..1..2....1..1..1....0..3..3
..0..1..0....0..3..2....0..3..1....1..0..0....1..1..2....2..1..2....3..3..0

Crossrefs

Sequence in context: A075668 A210175 A137733 * A347569 A250998 A119735

Adjacent sequences: A205633 A205634 A205635 * A205637 A205638 A205639

Keyword

nonn

Author

R. H. Hardin, Jan 29 2012

Status

approved