OFFSET
0,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..1000
FORMULA
EXAMPLE
a(6) = 5 because Lucas(6) = 21 and the sum of the prime divisors {3, 7} equals 10.
MAPLE
with (numtheory):with(combinat, fibonacci):
sopf:= proc(n) local e, j; e := ifactors(fibonacci(n+1)+fibonacci(n-1))[2]:
add (e[j][1], j=1..nops(e)) end:
seq (sopf(n), n=0..100);
MATHEMATICA
Array[If[#==1, 0, Plus@@First/@FactorInteger[LucasL[ # ]]]&, 50, 0]
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Nov 14 2012
EXTENSIONS
a(0) prepended by Amiram Eldar, Sep 03 2019
STATUS
approved