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A340767
Number of primes p <= 6*n + 5 that are congruent to 2 modulo 3.
2
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
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
KEYWORD
nonn,easy
AUTHOR
Jianing Song, Apr 28 2021
STATUS
approved