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A065694
Braided power sequence: A065692 is b(n+1) = 3*b(n) + 2*d(n) - c(n), A065693 is c(n+1) = 3*c(n) + 2*b(n) - d(n) and this is d(n+1) = 3*d(n) + 2*c(n) - b(n), starting with b(0) = 0, c(0) = 1 and d(0) = 2.
3
2, 8, 23, 47, 80, 365, 3089, 19916, 96287, 369983, 1188008, 3489557, 11440865, 49588820, 250207799, 1210364111, 5215038272, 20004134333, 70879879793, 248964475292, 941859229775, 3946659132575, 17384730325784, 75199501505381, 308325687691457, 1197353616486308
OFFSET
0,1
COMMENTS
Tends to 4^n. "Braided" because the order of b(n), c(n) and d(n) changes between the six possibilities as n increases.
FORMULA
From Colin Barker, Sep 02 2016: (Start)
a(n) = 9*a(n-1) - 33*a(n-2) + 52*a(n-3) for n > 2.
G.f.: (2 - 10*x + 17*x^2) / ((1 - 4*x)*(1 - 5*x + 13*x^2)). (End)
EXAMPLE
a(1) = 3*2 + 2*1 - 1*0 = 8.
PROG
(PARI) a(n) = {[0, 0, 1]*[3, -1, 2; 2, 3, -1; -1, 2, 3]^n*[0, 1, 2]~} \\ Andrew Howroyd, Dec 29 2024
CROSSREFS
Sequence in context: A303287 A321068 A158466 * A178129 A203298 A161463
KEYWORD
nonn,easy,changed
AUTHOR
Henry Bottomley, Nov 14 2001
EXTENSIONS
a(24) onwards from Andrew Howroyd, Dec 29 2024
STATUS
approved