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A268257 Number of length-(n+1) 0..4 arrays with new repeated values introduced in sequential order starting with zero. 1
21, 89, 378, 1610, 6877, 29461, 126591, 545627, 2359152, 10233188, 44533546, 194450722, 851923695, 3745257911, 16522347429, 73145533817, 324971178262, 1448957138290, 6483809640888, 29119030669064, 131250471466965 (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) = 21*a(n-1) - 170*a(n-2) + 634*a(n-3) - 899*a(n-4) - 401*a(n-5) + 1310*a(n-6) + 826*a(n-7) + 120*a(n-8).

Empirical g.f.: x*(21 - 352*x + 2079*x^2 - 4512*x^3 - 220*x^4 + 7524*x^5 + 4261*x^6 + 600*x^7) / ((1 - 4*x)*(1 - 5*x)*(1 - 4*x - x^2)*(1 - 4*x - 2*x^2)*(1 - 4*x - 3*x^2)). - Colin Barker, Jan 13 2019

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

..1....2....4....0....0....1....4....0....0....1....4....2....4....0....4....1

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

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

CROSSREFS

Column 4 of A268261.

Sequence in context: A304514 A219886 A211464 * A223370 A223363 A284440

Adjacent sequences:  A268254 A268255 A268256 * A268258 A268259 A268260

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 29 2016

STATUS

approved

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Last modified January 24 13:48 EST 2022. Contains 350538 sequences. (Running on oeis4.)