0,9

It appears that a(A046174(n)) = 0.

Table of n, a(n) for n=0..90.

(PARI) a(n) = sum(k=1, n-1, isprime((2*n^2+2*k*n-k^2-k)/2))

Cf. A046174.

Sequence in context: A181089 A341894 A171932 * A214664 A214666 A320471

Adjacent sequences: A305626 A305627 A305628 * A305630 A305631 A305632

nonn

Gionata Neri, Jul 08 2018

approved