OFFSET
1,20
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 10^1 + 19 = 29 is a prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 09 2003
EXTENSIONS
More terms from David Wasserman, May 24 2005
STATUS
approved