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A132805
A trisection of A024495.
8
0, 3, 21, 171, 1365, 10923, 87381, 699051, 5592405, 44739243, 357913941, 2863311531, 22906492245, 183251937963, 1466015503701, 11728124029611, 93824992236885, 750599937895083, 6004799503160661, 48038396025285291, 384307168202282325, 3074457345618258603
OFFSET
0,2
FORMULA
From Philippe Deléham, Nov 19 2007: (Start)
a(n) = A132804(n)/2.
G.f.: 3x/(1 - 7*x - 8*x^2).
a(n+1) = 7*a(n) + 8*a(n-1) for n >= 1, a(0)=0, a(1)=3. (End)
a(n) = 3*A015565(n). - R. J. Mathar, Aug 07 2017
MATHEMATICA
LinearRecurrence[{7, 8}, {0, 3}, 40] (* Harvey P. Dale, Feb 08 2015 *)
PROG
(Magma) [-(1/3)*(-1)^n+(1/3)*8^n: n in [0..25]]; // Vincenzo Librandi, Aug 10 2011
CROSSREFS
Cf. A029898.
Sequence in context: A370284 A046637 A220103 * A372459 A189475 A331328
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Nov 18 2007
STATUS
approved