OFFSET
1,2
COMMENTS
Most prime numbers are absent; from first 1000 primes only 138 are terms: 3, 11, 17, 41, 67, 83, 109, 127, 157, 191, 211, 241, 277, 283, 353, ..., all with prime indices. Also, all nonprimes are terms. - Zak Seidov, Sep 12 2015
LINKS
Zak Seidov, Table of n, a(n) for n = 1..10000
MATHEMATICA
s={1}; Do[If[ !PrimeQ[n]||(PrimeQ[n] && FreeQ[s, PrimePi[n]]), AppendTo[s, n]], {n, 2, 100}]; s (* Zak Seidov *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Aug 06 2006
STATUS
approved