A348193 (Number of primes == 3 mod 4 less than n^2) - (number of primes == 1 mod 4 less than n^2).

0, 1, 1, 1, 2, 2, 2, 1, 3, 2, 1, 3, 4, 3, 5, 5, 4, 3, 3, 3, 2, 3, 6, 6, 5, 5, 6, 4, 5, 5, 5, 5, 6, 4, 3, 3, 4, 3, 7, 12, 10, 7, 10, 8, 9, 10, 10, 7, 6, 6, 9, 8, 6, 6, 9, 6, 4, 9, 6, 8, 8, 7, 12, 11, 11, 9, 8, 9, 12, 9, 12, 17, 12, 13, 16, 12, 16, 18, 16, 15, 12, 12, 11, 17, 18, 14, 11, 13, 9, 5, 7, 7, 6, 7, 8, 7, 6, 8, 7, 10

Offset: 1

Author

Seiichi Manyama, Oct 06 2021

Keywords

• sign
• look

Comments

a(790) = -1.

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A014085, A077766, A077767, A091295, A348194, A348195, A348196.

Programs

PARI

a(n) = sum(k=2, n^2-1, (isprime(k)&&k%4==3)-(isprime(k)&&k%4==1));

Formula

a(n) = A348195(n) - A348196(n).