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A135423
a(n) = (5*9^n + 1)/2.
4
3, 23, 203, 1823, 16403, 147623, 1328603, 11957423, 107616803, 968551223, 8716961003, 78452649023, 706073841203, 6354664570823, 57191981137403, 514727830236623, 4632550472129603, 41692954249166423, 375236588242497803
OFFSET
0,1
FORMULA
a(n) = 9*a(n-1) - 4 for n>0, a(0)=3.
O.g.f.: (1/(1-x) - 5/(9*x-1))/2. - R. J. Mathar, Feb 19 2008
a(n) = 10*a(n-1) - 9*a(n-2). - Vincenzo Librandi, Nov 08 2011
E.g.f.: (1/2)*( 5*exp(9*x) + exp(x) ). - G. C. Greubel, Oct 14 2016
MATHEMATICA
Table[ (5*9^n + 1)/2, {n, 0, 25}] (* or *) LinearRecurrence[{10, -9}, {3, 23}, 25] (* G. C. Greubel, Oct 14 2016 *)
PROG
(Magma) [(5*9^n+1)/2: n in [0..30]]; // Vincenzo Librandi, Nov 08 2011
CROSSREFS
Bisection of A057198. Cf. A191450.
Sequence in context: A370283 A235131 A235360 * A114017 A316085 A068691
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Feb 18 2008
EXTENSIONS
More terms from R. J. Mathar, Feb 19 2008
Definition rewritten (with Mathar's formula) from Bruno Berselli, Nov 08 2011
STATUS
approved