A369247 Number of representations of 3*A057588(n) as a sum (p*q + p*r + q*r) with three odd primes p <= q <= r, where A057588 is Kummer numbers, one less than primorials.

0, 0, 1, 3, 2, 6, 10, 12, 50, 178, 150

Offset: 1

Author

Antti Karttunen, Jan 22 2024

Keywords

• nonn
• hard
• more

Crossrefs

Cf. A002110, A057588, A369054.

Programs

PARI

\\ Needs also program from A369054:
A002110(n) = prod(i=1,n,prime(i));
A369247(n) = A369054(3*(A002110(n)-1));

Formula

a(n) = A369054(3*(A002110(n)-1)).