A214132 Lesser term of smallest primitive friendly pair such that both terms are divisible by the n-th prime p and coprime to the primes below p.

6, 135, 14105, 15506071, 432712085377, 1890948943, 14783271043, 45847, 211838579, 147560225903398137982300169126840969637180767467, 12060713581457342807125295910808091355523729

Offset: 1

Author

Michel Marcus, Jul 05 2012

Keywords

• hard
• more
• nonn

Comments

For n>2, instances are known up to 11 (p=31).

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

Examples

			For n=1, the perfect numbers 6=2*3 and 28=2^2*7 (A214133) are primitive friendly.
For n=2, 135=3^3*5 and 819=3^2*7*13 (A214133) are primitive friendly.
		

Links

• Achim Flammenkamp, The Multiply Perfect Numbers Page (for p = 13, 17, 19)
• Michel Marcus, Table A214132 and A214133 for n = 1..11

Crossrefs

Cf. A214133. Subset of sequence A096366.