OFFSET
2,2
COMMENTS
Let f(k,n) = Sum_{i=1..n} Fibonacci(i)*k^(i-1) where Fibonacci(i) = A000045(i). Corresponding smallest primes of the form f(k,n) or f(a(n),n) are {2,11,7,7207,853211,46477210729,6554599,484440107670157,...}.
EXAMPLE
a(2) = 1 because f(1,2) = 1*1 + 1 = 2 is prime.
a(3) = 2 because f(2,3) = 2*2^2 + 1*2 + 1 = 11 is prime but f(1,3) = 2*1^2 + 1*1 + 1 = 4 is not prime.
a(4) = 1 because f(1,4) = 3*1^3 + 2*1^2 + 1*1 + 1 = 7 is prime.
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Alexander Adamchuk, Sep 02 2006
STATUS
approved