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A264337
Number of (n+1) X (4+1) arrays of permutations of 0..n*5+4 with each element having index change +-(.,.) 0,0 0,1 or 1,2.
1
181, 3567, 70669, 1399783, 27726581, 549201567, 10878455069, 215477871383, 4268134837381, 84542207852367, 1674592106593069, 33169925350906183, 657022055372706581, 13014137857695923967, 257780972182185860669
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 19*a(n-1) + 16*a(n-2).
Conjectures from Colin Barker, Jan 07 2019: (Start)
G.f.: x*(181 + 128*x) / (1 - 19*x - 16*x^2).
a(n) = (2^(-n)*((19-5*sqrt(17))^n*(-21+4*sqrt(17)) + (21+4*sqrt(17))*(19+5*sqrt(17))^n)) / sqrt(17).
(End)
EXAMPLE
Some solutions for n=3:
..0..2..1..4..3....0..8..1..3..4....7..1..3..2..4....0..2..1..4..3
.12..6..7..9..8...12..5..7..9..2....5.13..0..8..9....5..6.14..9..8
.17.10..5.14.13...17.11.13..6.14...11.10.12..6.14...11.10.12.13..7
.16.15.18.11.19...15.16.10.18.19...15.17.16.19.18...16.15.18.17.19
CROSSREFS
Column 4 of A264341.
Sequence in context: A069763 A264289 A200953 * A155018 A179814 A293655
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 11 2015
STATUS
approved