A209777 Number of q in the range 0<=q<=n for which A006002(n)+A006002(q) is prime.

1, 1, 0, 1, 0, 2, 1, 0, 0, 3, 0, 1, 2, 0, 0, 2, 1, 3, 1, 0, 0, 9, 1, 0, 2, 2, 0, 2, 1, 2, 4, 0, 0, 6, 1, 1, 5, 4, 1, 3, 2, 3, 2, 0, 0, 15, 0, 2, 2, 3, 3, 7, 1, 4, 2, 1, 3, 17, 2, 1, 6, 5, 1, 4, 2, 8, 3, 0, 0, 7, 2, 3, 9, 3, 1, 2, 0, 9, 1, 0, 2, 21, 1, 4, 6, 9, 2, 5, 2, 4, 6, 3, 3, 16, 2, 2, 4, 5, 1, 2

Offset

1,6

Links

Table of n, a(n) for n=1..100.

Example

a(6)=2 because 147+2 and 147+50 are primes;
a(10)=3 because 605+2, 605+224 and 605+324 are primes.

Prog

(PARI) a(n) = sum(q=0, n, isprime((n*(n+1)^2 + q*(q+1)^2)/2)); \\ Michel Marcus, Oct 16 2025

Crossrefs

Cf. A006002, A130504.

Sequence in context: A237053 A364022 A363900 * A356931 A377129 A356864

Adjacent sequences: A209774 A209775 A209776 * A209778 A209779 A209780

Keyword

nonn

Author

Gerasimov Sergey, Mar 27 2012

Extensions

Corrected by R. J. Mathar, Mar 30 2012

Status

approved