OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,6,0,-4).
FORMULA
a(n) = fibonacci(n+1)*2^[(n+1)/2]. a(n) = 6*a(n-2) - 4*a(n-4) for n>4. G.f.: (1+2*x-2*x^2)/(1-6*x^2+4*x^4).
EXAMPLE
Sequence begins: {1*1, 1*2, 2*2, 3*4, 5*4, 8*8, 13*8, 21*16, 34*16, ...}.
MATHEMATICA
LinearRecurrence[{0, 6, 0, -4}, {1, 2, 4, 12}, 30] (* Harvey P. Dale, Aug 09 2016 *)
PROG
(PARI) a(n)=fibonacci(n+1)*2^((n+1)\2)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 25 2004
STATUS
approved