A263746 - OEIS

A263746

Number of length n arrays of permutations of 0..n-1 with each element moved by -2 to 2 places and every three consecutive elements having its maximum within 5 of its minimum.

1, 2, 6, 14, 31, 73, 160, 357, 814, 1836, 4140, 9379, 21163, 47769, 107940, 243763, 550469, 1243468, 2808345, 6342601, 14325494, 32354798, 73074320, 165043749, 372759852, 841897006, 1901473298, 4294581633, 9699541870, 21906956858

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OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3) - 3*a(n-5) + 7*a(n-6) - a(n-7) - 2*a(n-8) - 5*a(n-9) - 3*a(n-10) + 2*a(n-11) + 2*a(n-13).

Empirical g.f.: x*(1 + x + 2*x^2 + 2*x^3 + x^4 + 5*x^5 - 4*x^6 - 6*x^7 - 5*x^8 - 2*x^9 + 3*x^10 + x^11 + 2*x^12) / (1 - x - 2*x^2 - 2*x^3 + 3*x^5 - 7*x^6 + x^7 + 2*x^8 + 5*x^9 + 3*x^10 - 2*x^11 - 2*x^13). - Colin Barker, Jan 03 2019

EXAMPLE

Some solutions for n=10:

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

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

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

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

..6....4....5....2....4....4....5....4....2....5....6....5....4....6....3....2

..5....6....6....6....5....6....6....3....7....3....7....4....6....5....5....3

..4....5....4....7....6....8....4....8....6....8....4....7....5....4....6....6

..9....7....7....5....7....5....8....7....5....6....5....8....8....8....8....7

..7....9....9....9....8....9....7....6....9....9....8....6....7....7....9....8

..8....8....8....8....9....7....9....9....8....7....9....9....9....9....7....9

CROSSREFS

Column 2 of A263752.

Sequence in context: A263711 A263697 A291409 * A002524 A188493 A055292

Adjacent sequences: A263743 A263744 A263745 * A263747 A263748 A263749

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 25 2015

STATUS

approved