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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
1, 4, 65, 3130, 178998, 10502458, 618242826, 36410671102, 2144479610070, 126304554589462, 7439032094765766, 438141046109721622, 25805450786659366998, 1519878816318690262678, 89517196729004371783830 (list; graph; refs; listen; history; text; internal format)
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: A293562 A307169 A307185 * A266520 A241705 A015475

Adjacent sequences:  A206497 A206498 A206499 * A206501 A206502 A206503

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 08 2012

STATUS

approved

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Last modified December 13 03:41 EST 2019. Contains 329968 sequences. (Running on oeis4.)