1,1

By definition, GCD(a(n), A002110(n-1)) = 1. - Michel Marcus, Jan 19 2014

Table of n, a(n) for n=1..9.

For n=1, the perfect numbers 6=2*3 (A214132) and 28=2^2*7 are primitive friendly.

For n=2, 135=3^3*5 (A214132) and 819=3^2*7*13 are primitive friendly.

Cf. A214132. Subset of sequence A096366.

Sequence in context: A041365 A042514 A158659 * A119055 A324450 A326279

Adjacent sequences: A214130 A214131 A214132 * A214134 A214135 A214136

nonn

Michel Marcus, Jul 05 2012

a(7) corrected and a(8)-a(9) added by Michel Marcus, Jun 18 2016

approved