1,2
Table of n, a(n) for n=1..43.
1*((2*3)^2)-1=35 composite
2*((2*3)^2)-1=71 prime 2*((2*3)^2)+1=73 prime twin of 71 so a(2)=2
Sequence in context: A127817 A199173 A047232 * A210963 A210965 A189959
Adjacent sequences: A103554 A103555 A103556 * A103558 A103559 A103560
nonn
Pierre CAMI, Mar 23 2005
approved