A206272 Number of (n+1) X 4 0..2 arrays with no 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward or upward neighbors.

1233, 3168, 12429, 39306, 133866, 437340, 1528920, 4972464, 17378730, 56812524, 197823117, 647998686, 2252305758, 7394389266, 25660071480, 84368598492, 292322882925, 962789033730, 3330544867176, 10985542604052, 37947971462754

Offset

1,1

Comments

Column 3 of A206277.

Links

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

Formula

Empirical: a(n) = 12*a(n-2) +22*a(n-4) +2*a(n-5) -340*a(n-6) +44*a(n-7) -30*a(n-8) +302*a(n-9) -3011*a(n-10) +198*a(n-11) +10251*a(n-12) -5274*a(n-13) +71024*a(n-14) -31264*a(n-15) -65095*a(n-16) +356*a(n-17) -100260*a(n-18) -55796*a(n-19) +285507*a(n-20) -129166*a(n-21) -253871*a(n-22) +145844*a(n-23) -497761*a(n-24) -139938*a(n-25) +558865*a(n-26) -259172*a(n-27) +120937*a(n-28) -90988*a(n-29) -849840*a(n-30) -208948*a(n-31) -309854*a(n-32) +4632*a(n-33) +119043*a(n-34) +74848*a(n-35) +43437*a(n-36) +90324*a(n-37) +60444*a(n-38) +22592*a(n-39) +12708*a(n-40) +4144*a(n-41) +8976*a(n-42) +1024*a(n-43) +1024*a(n-44) for n>49.

Example

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

Crossrefs

Sequence in context: A182721 A183881 A270540 * A064942 A101311 A055616

Adjacent sequences: A206269 A206270 A206271 * A206273 A206274 A206275

Keyword

nonn

Author

R. H. Hardin, Feb 05 2012

Status

approved