A295169 a(n) = smallest number k with n prime factors such that (2d)^2 + (k/d)^2 is prime for every d | k.

1, 3, 65, 5757

Offset

0,2

Comments

Such k must be an odd squarefree number.

Conjecture: the sequence is infinite.

a(4) > 10^10 if it exists. - Charles R Greathouse IV, Nov 28 2017

Links

Table of n, a(n) for n=0..3.

Crossrefs

Subsequence of A236423(n+1)/2 for n > 0.

Cf. A295124.

Sequence in context: A348084 A012837 A036778 * A065400 A306410 A091470

Adjacent sequences: A295166 A295167 A295168 * A295170 A295171 A295172

Keyword

nonn,more

Author

Thomas Ordowski, Nov 16 2017

Extensions

a(3) from Paolo P. Lava, Nov 16 2017

Status

approved