A340767 Number of primes p <= 6*n + 5 that are congruent to 2 modulo 3.

2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 10, 11, 11, 12, 13, 13, 14, 15, 16, 16, 16, 17, 18, 18, 19, 19, 19, 20, 21, 22, 22, 23, 24, 24, 24, 24, 24, 25, 26, 27, 27, 28, 29, 30, 31, 31, 32, 32, 33, 33, 33, 34, 35, 35, 35, 35, 35, 36, 37, 38, 38, 38, 38, 39, 40, 40, 41, 41, 41, 42, 42

Offset

0,1

Links

Jianing Song, Table of n, a(n) for n = 0..10000

Formula

a(n) = A340764(6*n+5).

a(n) = 1 + Sum_{k=0..n+1} A167020(k).

Example

There are 14 primes <= 6*16+5 = 101 that are congruent to 2 modulo 3, namely 2, 5, 11, 17, 23, 29, 41, 47, 53, 59, 71, 83, 89, 101, so a(16) = 14.

Prog

(PARI) a(n) = sum(i=1, 6*n+5, isprime(i) && (i%3==2))

Crossrefs

Cf. A003627, A167020, A340764, A172104, A296021, A296020.

Sequence in context: A278055 A291764 A319681 * A099848 A082287 A331267

Adjacent sequences: A340764 A340765 A340766 * A340768 A340769 A340770

Keyword

nonn,easy

Author

Jianing Song, Apr 28 2021

Status

approved