A295124 a(n) = smallest number k with n prime factors such that 2d + k/d is prime for every d | k.

1, 3, 15, 105, 93081

Offset: 0

Author

Thomas Ordowski, Nov 15 2017

Keywords

• nonn
• more

Comments

Such k must be an odd squarefree number.

a(n) has 2^n divisors and each gives another prime.

Conjecture: the sequence is infinite. It is hard to believe!

a(n) is the smallest k such that A088627(k) = A000005(k) = 2^n.

Crossrefs

Cf. A088627, A293756.

Subsequence of A244520 (2d + k/d is prime for every d|k).

Formula

a(n) = A293756(n+1)/2.

Extensions

a(4) from Michel Marcus, Nov 15 2017