A220339 Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their king-move neighbors in a random 0..3 nX2 array

1, 5, 24, 89, 389, 1570, 6413, 25744, 103229, 412081, 1643706, 6548560, 26080372, 103836793, 413362985, 1645415613, 6549395074, 26068520679, 103759005831, 412983036406, 1643754108417, 6542452940294, 26040170803581, 103644625748031

Offset

1,2

Comments

Column 2 of A220342

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +6*a(n-2) -22*a(n-3) -15*a(n-4) +10*a(n-5) +56*a(n-6) +34*a(n-7) -68*a(n-8) -12*a(n-9) -247*a(n-10) +258*a(n-11) +429*a(n-12) -176*a(n-13) -798*a(n-14) +50*a(n-15) +1112*a(n-16) -368*a(n-17) -628*a(n-18) +288*a(n-19) -56*a(n-20) -248*a(n-21) +96*a(n-22)

Example

Some solutions for n=3
..1..1....0..0....0..0....0..0....1..0....0..1....1..0....1..1....1..1....0..0
..0..0....0..1....0..0....1..1....0..0....0..0....0..0....1..0....0..0....0..0
..0..0....0..0....1..0....0..1....0..1....0..1....0..0....0..0....1..1....0..0

Crossrefs

Sequence in context: A272420 A089095 A220316 * A158499 A074085 A145914

Adjacent sequences: A220336 A220337 A220338 * A220340 A220341 A220342

Keyword

nonn

Author

R. H. Hardin Dec 11 2012

Status

approved