OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,1).
FORMULA
From Elmo R. Oliveira, Mar 31 2026: (Start)
G.f.: -(15*x - 2)/(x^2 + x - 1).
a(n) = a(n-1) + a(n-2) for n > 2.
a(n) = 13*Fibonacci(n) - 2*Fibonacci(n-1). (End)
MAPLE
a:= n-> (<<0|1>, <1|1>>^n.<<-2, 13>>)[1, 1]:
seq(a(n), n=1..36); # Alois P. Heinz, Mar 31 2026
MATHEMATICA
LinearRecurrence[{1, 1}, {13, 11}, 80]
PROG
(Magma) I:=[13, 11]; [n le 2 select I[n] else Self(n-1)+Self(n-2): n in [1..50]]; // Vincenzo Librandi, Feb 16 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, Feb 10 2012
STATUS
approved