OFFSET
1,1
COMMENTS
One less than count of members of n-th maximal chain of primes. For definitions see A152658.
LINKS
Klaus Brockhaus, Table of n, a(n) for n=1..1000
EXAMPLE
The consecutive primes 5, 7, 11 form the first maximal chain of primes (see example in A152658); it has three members, two links. Therefore a(1) = 2.
PROG
(PARI) {n=1; while(n<560, c=0; while(isprime(n*prime(n)+(n+1)*prime(n+1)), c++; n++); if(c>0, print1(c, ", ")); n++)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Dec 16 2008
STATUS
approved