OFFSET
1,11
COMMENTS
Most of the terms are 0, 1 or 2. Subsidiary sequence: Index of the first occurrence of n. Conjecture: There exists a finite M such that a(n) < M for all n.
EXAMPLE
a(10) = 1 as 3^1 + 20 = 23 is a prime.
a(23) = 3 as 3^3 +46 = 73 is a prime but 46+3 and 46+9 are not.
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 09 2003
EXTENSIONS
More terms from David Wasserman, May 24 2005
STATUS
approved