cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

1, 3, 15, 105, 93081
Offset: 0

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Author

Thomas Ordowski, Nov 15 2017

Keywords

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
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