A206103 Number of (n+1) X 3 0..3 arrays with the number of clockwise edge increases in 2 X 2 subblocks nondecreasing, and counterclockwise edge increases nonincreasing, rightwards and downwards.

2292, 33688, 359932, 3991540, 48804116, 628383700, 8315311380, 111777355164, 1517380463868, 20726390613512, 284225008359808, 3907377273935812, 53801817656893772, 741558531562612620, 10227540037356314924

Offset

1,1

Comments

Column 2 of A206109.

Links

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

Formula

Empirical: a(n) = 33*a(n-1) -360*a(n-2) +1064*a(n-3) +6623*a(n-4) -48843*a(n-5) +36454*a(n-6) +462146*a(n-7) -1108534*a(n-8) -1366630*a(n-9) +7140184*a(n-10) -1697512*a(n-11) -21255050*a(n-12) +19737170*a(n-13) +32688340*a(n-14) -52426948*a(n-15) -21931877*a(n-16) +72556685*a(n-17) -6515536*a(n-18) -57641680*a(n-19) +23396587*a(n-20) +24953529*a(n-21) -17722570*a(n-22) -4107694*a(n-23) +6031452*a(n-24) -678024*a(n-25) -742672*a(n-26) +256704*a(n-27) -23040*a(n-28) for n>33.

Example

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

Crossrefs

Sequence in context: A268892 A206663 A247990 * A251302 A198146 A020404

Adjacent sequences: A206100 A206101 A206102 * A206104 A206105 A206106

Keyword

nonn

Author

R. H. Hardin, Feb 03 2012

Status

approved