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A264239 Number of (n+1) X (3+1) arrays of permutations of 0..n*4+3 with each element having directed index change 0,0 1,1 0,-1 -1,1 or 0,-2. 1
21, 95, 804, 5055, 36193, 243881, 1688581, 11546272, 79399773, 544596821, 3739740969, 25667019555, 176203806580, 1209502867667, 8302721830885, 56993334702205, 391230050623617, 2685581075271584, 18435090548352201 (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) = 7*a(n-1) + 7*a(n-2) - 65*a(n-3) + 65*a(n-4) + 62*a(n-5) - 72*a(n-6).

Empirical g.f.: x*(1 + x)*(21 - 73*x + 65*x^2 + 62*x^3 - 72*x^4) / (1 - 7*x - 7*x^2 + 65*x^3 - 65*x^4 - 62*x^5 + 72*x^6). - Colin Barker, Jan 06 2019

EXAMPLE

Some solutions for n=4:

..1..2..5..3....0..1..5..3....0..4..2..3....1..4..3..6....1..4..2..3

..4..0..6..7....4..8..7..2....6..8..1..7....5..0..7..2....5..0..6..7

..9.11.13.14...10.12.11..6...10.12..5.11....8..9.13.11....8..9.13.11

.12..8.15.10...13.14..9.15...14.16..9.15...12.14.15.10...14.15.17.10

.16.17.18.19...16.17.18.19...18.17.13.19...16.17.18.19...16.12.18.19

CROSSREFS

Column 3 of A264244.

Sequence in context: A174084 A193218 A220157 * A200255 A212406 A288750

Adjacent sequences:  A264236 A264237 A264238 * A264240 A264241 A264242

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 09 2015

STATUS

approved

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Last modified July 30 07:18 EDT 2021. Contains 346348 sequences. (Running on oeis4.)