login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A198645
a(n) = 10*3^n - 1.
3
9, 29, 89, 269, 809, 2429, 7289, 21869, 65609, 196829, 590489, 1771469, 5314409, 15943229, 47829689, 143489069, 430467209, 1291401629, 3874204889, 11622614669, 34867844009, 104603532029, 313810596089, 941431788269, 2824295364809
OFFSET
0,1
FORMULA
a(n) = 3*a(n-1) + 2, a(0)=9.
G.f. ( 9-7*x ) / ( (3*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011
MATHEMATICA
10 * 3^Range[0, 30]-1 (* Harvey P. Dale, Feb 28 2022 *)
PROG
(Magma) [10*3^n-1: n in [0..30]]
CROSSREFS
Cf. A048473.
Sequence in context: A318742 A024922 A193004 * A045862 A035075 A103535
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 28 2011
STATUS
approved