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A198644
8*3^n-1.
3
7, 23, 71, 215, 647, 1943, 5831, 17495, 52487, 157463, 472391, 1417175, 4251527, 12754583, 38263751, 114791255, 344373767, 1033121303, 3099363911, 9298091735, 27894275207, 83682825623, 251048476871, 753145430615, 2259436291847, 6778308875543
OFFSET
0,1
FORMULA
a(n) = 3*a(n-1)+2, a(0)=7.
G.f. ( 7-5*x ) / ( (3*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011
MATHEMATICA
8*3^Range[0, 30]-1 (* or *) LinearRecurrence[{4, -3}, {7, 23}, 30] (* Harvey P. Dale, Jun 16 2024 *)
PROG
(Magma) [8*3^n-1: n in [0..30]]
CROSSREFS
Sequence in context: A005342 A139852 A141194 * A045535 A001984 A147972
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 28 2011
STATUS
approved