OFFSET
1,1
COMMENTS
Conjecture: for k > 5, prime(n) <= k < prime(n+1) <= k + pi(k), i.e., the smallest prime greater than k is <= k + pi(k). Equality holds for k = 7.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
21 is a member as 21 + pi(21) = 21 + 8 = 29 is a prime.
MATHEMATICA
Select[Range[350], PrimeQ[#+PrimePi[#]]&] (* Harvey P. Dale, Nov 19 2011 *)
PROG
(PARI) for(n=1, 200, if(isprime(n+primepi(n)), print1(n, ", "))) \\ Derek Orr, Jun 22 2015
(PARI) pi=0; p=2; forprime(q=3, 1e3, pi++; for(n=p, q-1, if(isprime(n+pi), print1(n", "))); p=q) \\ Charles R Greathouse IV, Jun 23 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Nov 08 2002
EXTENSIONS
More terms from David Garber, Nov 10 2002
STATUS
approved