OFFSET
1,4
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(40) = 2 because 40 = 5*8; 5 and 8 are Fibonacci numbers but 40 is not.
MAPLE
N:= 1000: # to get a(1) to a(N)
A:= Vector(N):
for i from 1 do
f:= combinat:-fibonacci(i);
if f > N then break fi;
A[f]:= 1
od:
for n from 1 to N do
if A[n] = 0 then
m:= floor(n/2);
r:= min(A[1..m] + A[[seq(n-i, i=1..m)]]);
for a in select(`<=`, numtheory:-divisors(n) minus {1}, floor(sqrt(n))) do
r:= min(r, A[a] + A[n/a])
od:
A[n]:= r;
fi
od:
seq(A[i], i=1..N);
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Jan 25 2015
STATUS
approved