OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-3).
FORMULA
a(n) = 3*a(n-1)-2 = A005032(n)+1.
a(n) = 4*a(n-1)-3*a(n-2).
G.f.: 2*(4-5*x)/((1-x)*(1-3*x)). a(n) = 2*A199109(n). - Bruno Berselli, Nov 03 2011
MATHEMATICA
7*3^Range[0, 30] + 1 (* Paolo Xausa, Jan 28 2025 *)
PROG
(Magma) [7*3^n+1: n in [0..30]];
(Python)
def a(n): return 7*3**n + 1
print([a(n) for n in range(26)]) # Michael S. Branicky, Aug 22 2021
CROSSREFS
KEYWORD
nonn,easy,changed
AUTHOR
Vincenzo Librandi, Nov 03 2011
STATUS
approved