A302443 Number of primes of the form b^2-3 for b <= 10^n.

3, 19, 119, 849, 6663, 54514, 460019, 3982973, 35174007

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Example

a(1) = 3 because there are 3 primes of the form b^2-3 for b <= 10 : 13, 61 and 97.

Prog

(PARI) {a(n) = sum(k=0, 10^n, isprime(k^2-3))}

Crossrefs

Number of primes of the form b^2+m for b <= 10^n: this sequence (m=-3), A302442 (m=-2), A206709 (m=1), A302434 (m=2), A302435 (m=3).

Cf. A028874.

Sequence in context: A221184 A274852 A139176 * A126809 A340644 A020073

Adjacent sequences: A302440 A302441 A302442 * A302444 A302445 A302446

Keyword

nonn,more

Author

Seiichi Manyama, Apr 08 2018

Status

approved