OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Amya Luo, Pattern Avoidance in Nonnesting Permutations, Undergraduate Thesis, Dartmouth College (2024). See p. 11.
Index entries for linear recurrences with constant coefficients, signature (4,-3).
FORMULA
a(n) = 3*a(n-1)+2 = 2*A060816(n+1).
G.f.: ( 4-2*x ) / ( (3*x-1)*(x-1) ). - R. J. Mathar, Nov 17 2011
MATHEMATICA
5*3^Range[0, 30] - 1 (* or *)
NestList[3*# + 2 &, 4, 30] (* Paolo Xausa, Aug 28 2024 *)
PROG
(Magma) [5*3^n-1: n in [0..30]];
(PARI) a(n)=5*3^n-1 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 28 2011
STATUS
approved