A348193 - OEIS

%I #17 Oct 07 2021 07:21:31

%S 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,

%T 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,

%U 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

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

%C a(790) = -1.

%H Seiichi Manyama, <a href="/A348193/b348193.txt">Table of n, a(n) for n = 1..10000</a>

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

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

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

%K sign,look

%O 1,5

%A _Seiichi Manyama_, Oct 06 2021