0,1

The sum of the reciprocals appears to converge.

(PARI) triprimes(n) = { sr = 0; for(j=1, n, x = j*(j+1)/2 +j; z = prime(x); sr+=1.0/z; print1(z" "); ); print(); print(sr); }

Primes in second diagonal from right in triangle in A078721.

Sequence in context: A121509 A096071 A159791 this_sequence A141187 A107138 A145473

Adjacent sequences: A078720 A078721 A078722 this_sequence A078724 A078725 A078726

easy,nonn

Cino Hilliard (hillcino368(AT)gmail.com), Dec 20 2002