A292330 Numbers k such that k^2 divides 4^k + 1.

1, 5, 205, 168305, 2084645, 37217545, 1711493545, 2483072545, 2763736405, 8866165745, 30555604445, 55328770405, 169592124685, 378465215105, 423977184745, 2038602559445, 3815777985545, 7279122076645, 25250364710105, 28104435502445, 45424920502505, 55625535217765, 90160039460905

Offset: 1

Author

Max Alekseyev, Sep 14 2017

Keywords

• nonn

Crossrefs

Cf. A052539. Subsequence of A015950.

Cf. A127104, A128678.