login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A113178
a(n) = Sum_{p|n} F(p), where F(p) is the p-th Fibonacci number and where the sum is over the distinct prime divisors of n.
2
0, 1, 2, 1, 5, 3, 13, 1, 2, 6, 89, 3, 233, 14, 7, 1, 1597, 3, 4181, 6, 15, 90, 28657, 3, 5, 234, 2, 14, 514229, 8, 1346269, 1, 91, 1598, 18, 3, 24157817, 4182, 235, 6, 165580141, 16, 433494437, 90, 7, 28658, 2971215073, 3, 13, 6, 1599, 234
OFFSET
1,3
LINKS
FORMULA
Additive with a(p^e) = F(p).
EXAMPLE
12 = 2^2 * 3^1, so a(12) = F(2) + F(3) = 1 + 2 = 3.
MATHEMATICA
b[t_]:=Fibonacci[First[t]] a[n_]:=Apply[Plus, Map[b, FactorInteger[n]]] (* Esa Peuha, Oct 26 2005 *)
PROG
(Sage) [0]+[sum([fibonacci(p) for p in prime_factors(n)]) for n in range(2, 53)] # Danny Rorabaugh, Apr 03 2015
CROSSREFS
Sequence in context: A114901 A355562 A194809 * A108362 A171090 A141506
KEYWORD
nonn,easy
AUTHOR
Leroy Quet, Oct 16 2005
EXTENSIONS
More terms from Esa Peuha (esa.peuha(AT)helsinki.fi), Oct 26 2005
STATUS
approved