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A274751 Number of 4 X n 0..2 arrays with no element equal to any value at offset (-1,-2) (0,-1) or (-1,0) and new values introduced in order 0..2. 1
4, 27, 144, 813, 4554, 25585, 143634, 806695, 4529786, 25438375, 142850048, 802197187, 4504820208, 25297392889, 142060454416, 797757713921, 4479903521254, 25157436233205, 141274594599246, 793344420605515 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 20*a(n-2) + 10*a(n-3) - 44*a(n-4) - 20*a(n-5) + 31*a(n-6) + 2*a(n-7) - 4*a(n-8).

Empirical g.f.: x*(4 + 19*x + 10*x^2 - 55*x^3 - 46*x^4 + 45*x^5 + 6*x^6 - 6*x^7) / ((1 + x - x^2)*(1 - 3*x - 16*x^2 + 3*x^3 + 25*x^4 - 2*x^5 - 4*x^6)). - Colin Barker, Jan 30 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Row 4 of A274749.

Sequence in context: A034512 A240194 A278358 * A015534 A306054 A218274

Adjacent sequences:  A274748 A274749 A274750 * A274752 A274753 A274754

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 04 2016

STATUS

approved

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Last modified December 7 20:40 EST 2021. Contains 349589 sequences. (Running on oeis4.)