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A171498
a(n) = 4*3^n-1.
12
3, 11, 35, 107, 323, 971, 2915, 8747, 26243, 78731, 236195, 708587, 2125763, 6377291, 19131875, 57395627, 172186883, 516560651, 1549681955, 4649045867, 13947137603, 41841412811, 125524238435, 376572715307, 1129718145923, 3389154437771, 10167463313315, 30502389939947
OFFSET
0,1
COMMENTS
Binomial transform of A171497.
Inverse binomial transform of A171499.
FORMULA
a(n) = 3*a(n-1)+2 for n > 0; a(0) = 3.
G.f.: (3-x)/((1-x)*(1-3*x)).
a(n) = A036543(n) + 2. - Philippe Deléham, Apr 13 2013
E.g.f.: exp(x)*(4*exp(2*x) - 1). - Stefano Spezia, Aug 04 2024
MATHEMATICA
NestList[3#+2&, 3, 30] (* Harvey P. Dale, Feb 25 2011 *)
PROG
(PARI) {m=25; v=concat([3], vector(m-1)); for(n=2, m, v[n]=3*v[n-1]+2); v}
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, Dec 10 2009
EXTENSIONS
a(25)-a(27) from Stefano Spezia, Aug 04 2024
STATUS
approved