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A264273 Number of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having index change +-(.,.) 0,0 1,0 or 1,2. 1
9, 48, 256, 1280, 6400, 32000, 160000, 800000, 4000000, 20000000, 100000000, 500000000, 2500000000, 12500000000, 62500000000, 312500000000, 1562500000000, 7812500000000, 39062500000000, 195312500000000, 976562500000000 (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) = 5*a(n-1) for n>3.

Conjectures from Colin Barker, Jan 07 2019: (Start)

G.f.: x*(9 + 3*x + 16*x^2) / (1 - 5*x).

a(n) = 256*5^(n-3) for n>2.

(End)

EXAMPLE

Some solutions for n=4:

..7..1..9..8..4....5..8..9..3..4....5..1..2..3..4....7..1..2..3..4

.12.13..0..3..2....0.11..7..1..2....0.11..7.13..9....0.11.12..8.14

.10.11..5..6.14...10..6.12.13.14...10..6.12..8.14...10..6..5.13..9

CROSSREFS

Row 2 of A264272.

Sequence in context: A115053 A181959 A171011 * A226751 A073584 A007037

Adjacent sequences:  A264270 A264271 A264272 * A264274 A264275 A264276

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 10 2015

STATUS

approved

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Last modified December 3 23:53 EST 2020. Contains 338920 sequences. (Running on oeis4.)