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A206391 Number of n X 3 0..5 arrays with no element equal to another within a city block distance of two, and new values 0..5 introduced in row major order. 1
1, 4, 26, 206, 1592, 12428, 96632, 752552, 5856992, 45595664, 354918176, 2762807264, 21506309504, 167411006144, 1303169775488, 10144214859392, 78965192918528, 614685592164608, 4784872150020608, 37246687385693696 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A206396.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) + 18*a(n-2) - 32*a(n-3) for n>5.

Empirical g.f.: x*(1 - 2*x - 16*x^2 + 10*x^3 + 16*x^4) / (1 - 6*x - 18*x^2 + 32*x^3). - Colin Barker, Jun 16 2018

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

  3 4 5    3 4 5    2 3 4    2 3 0    2 3 4    3 4 5    2 3 0

  5 0 1    1 0 3    4 5 1    4 5 1    1 5 0    1 0 3    1 4 5

  4 3 2    2 5 1    3 2 0    0 2 4    4 2 3    4 5 1    5 0 1

CROSSREFS

Cf. A206396.

Sequence in context: A118971 A124554 A321586 * A228966 A291533 A239295

Adjacent sequences:  A206388 A206389 A206390 * A206392 A206393 A206394

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 07 2012

STATUS

approved

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Last modified May 26 16:47 EDT 2019. Contains 323597 sequences. (Running on oeis4.)