A172104 Partial sums of A167021 where A167021(n)=1 iff 6*n+1 is prime.

1, 2, 3, 3, 4, 5, 6, 6, 6, 7, 8, 9, 10, 10, 10, 11, 12, 13, 13, 13, 14, 14, 15, 15, 16, 17, 18, 18, 18, 19, 19, 20, 21, 21, 22, 22, 23, 24, 24, 25, 25, 25, 25, 25, 26, 27, 28, 28, 28, 28, 29, 30, 30, 30, 31, 32, 32, 33, 33, 33, 34, 35, 36, 36, 36, 37, 37, 38, 38, 39, 39, 40, 41

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 25 2010

Keywords

• nonn

Comments

Where A167021 is the characteristic sequence: A167021(n)=1 iff 6*n+1 is prime.

Crossrefs

Cf. A002476, A167021, A172103.

Programs

PARI

isp(n) = isprime(6*n+1); \\ A167021
a(n) = sum(k=1, n, isp(k)); \\ Michel Marcus, Feb 06 2019

Extensions

Entries checked by R. J. Mathar, Apr 24 2010