A206500 Number of nX3 0..7 arrays with no element equal to another within a city block distance of two, and new values 0..7 introduced in row major order

1, 4, 65, 3130, 178998, 10502458, 618242826, 36410671102, 2144479610070, 126304554589462, 7439032094765766, 438141046109721622, 25805450786659366998, 1519878816318690262678, 89517196729004371783830

Offset

1,2

Comments

Column 3 of A206503

Links

R. H. Hardin, Table of n, a(n) for n = 1..62

Formula

Empirical: a(n) = 55*a(n-1) +370*a(n-2) -8556*a(n-3) +15608*a(n-4) +70028*a(n-5) -175808*a(n-6) +98304*a(n-7) for n>9

Example

Some solutions for n=4
..0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2
..2..3..0....2..3..0....2..3..0....3..4..0....2..3..4....2..3..4....2..3..4
..1..4..5....4..5..1....1..4..5....2..5..1....1..0..5....1..5..6....4..5..1
..5..0..1....1..0..4....5..2..1....0..3..6....3..4..2....3..4..7....6..2..3

Crossrefs

Sequence in context: A307169 A335176 A307185 * A266520 A241705 A015475

Adjacent sequences: A206497 A206498 A206499 * A206501 A206502 A206503

Keyword

nonn

Author

R. H. Hardin Feb 08 2012

Status

approved