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A222868 Number of n X 2 0..5 arrays with no element equal to another at a city block distance of exactly two, and new values 0..5 introduced in row major order. 1
2, 7, 34, 370, 5314, 82690, 1313794, 20983810, 335593474, 5368905730, 85900132354, 1374392680450, 21990245138434, 351843771219970, 5629499735539714, 90071993352716290, 1441151883979784194, 23058430105021841410 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A222871.

LINKS

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

FORMULA

Empirical: a(n) = 21*a(n-1) - 84*a(n-2) + 64*a(n-3) for n>5.

Empirical g.f.: x*(2 - 35*x + 55*x^2 + 116*x^3 - 48*x^4) / ((1 - x)*(1 - 4*x)*(1 - 16*x)). - Colin Barker, Aug 16 2018

EXAMPLE

Some solutions for n=3:

..0..0....0..1....0..0....0..0....0..1....0..1....0..1....0..1....0..1....0..1

..1..2....2..2....1..2....1..2....2..3....0..2....0..2....2..1....2..3....2..3

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

CROSSREFS

Cf. A222871.

Sequence in context: A110313 A000944 A136310 * A222777 A222891 A231580

Adjacent sequences:  A222865 A222866 A222867 * A222869 A222870 A222871

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 07 2013

STATUS

approved

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Last modified November 22 13:47 EST 2019. Contains 329393 sequences. (Running on oeis4.)