1,2

Number m is in the sequence iff 1) there exists only composite number k such that 2*k-1 is prime and A060715(k)=m; 2) there is no prime p such that 2*p-1 is prime and A060715(p)=m-1.

Table of n, a(n) for n=1..59.

A194217(n)=0.

Cf. A104272, A080359, A164554, A193507, A194184, A194186, A194217, A182366.

Sequence in context: A077788 A339048 A137018 * A346465 A263722 A299971

Adjacent sequences: A182388 A182389 A182390 * A182392 A182393 A182394

nonn

Vladimir Shevelev, Apr 27 2012

approved