A306502 a(n) is the index in primes of A306499(n), or 0 if A306499(n) = 0.

1, 102091236, 732722, 6181, 314, 1, 199, 3, 2, 128, 1, 5, 2, 1, 4, 7, 5, 1, 4, 3, 1, 6, 1, 2, 9, 4, 2, 1, 6, 8, 1, 9, 7, 1, 3, 1, 4, 2, 1, 6, 2, 1, 8, 4, 1, 11, 11, 3, 7, 1, 6, 6, 2, 15, 1, 3, 2, 1, 12, 1, 15, 1, 3, 4, 1, 14, 1, 2, 5, 3, 2, 1, 10, 16, 1, 13, 1, 8, 1

Offset: 1

Author

Jianing Song, Feb 19 2019

Keywords

• nonn

Comments

a(n) is the smallest integer k such that Sum_{i=1..k} Kronecker(A003658(n),prime(i)) > 0, or 0 if no such k exists.

See A306499 for the actual primes.

Examples

			See A306499 for the example that shows a(16) = 7.
		

Crossrefs

Cf. A003658, A306499, A306503.

Programs

PARI

b(n) = my(i=0); forprime(p=2, oo, i+=kronecker(n, p); if(i>0, return(p)))
for(n=1, 300, if(isfundamental(n), print1(primepi(b(n)), ", ")))

Sage

# uses[KroneckerSum from A306499]
A306499 = KroneckerSum()
print([prime_pi(next(A306499)) for  in range(77)]) # _Peter Luschny, Feb 26 2019