OFFSET
1,1
COMMENTS
Conjecture: the sequence is infinite.
LINKS
K. D. Bajpai and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 3000 terms from Bajpai)
EXAMPLE
a(6) = 21 : n^2+pi(n ) = 21^2 + pi(21) = 441+8 = 449 which is a prime.
MAPLE
with(numtheory): KD:= proc() local a; a:= n^2+pi(n); if isprime(a) then RETURN(n): fi; end: seq(KD(), n=1..2000);
MATHEMATICA
Select[Range[600], PrimeQ[#^2+PrimePi[#]]&] (* Harvey P. Dale, Jul 04 2018 *)
PROG
(PARI) v=List(); p=0; for(n=2, 1e4, p+=isprime(n); if(isprime(n^2+p), listput(v, n))); Vec(v) \\ Charles R Greathouse IV, Sep 04 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Sep 04 2013
STATUS
approved