A338128 a(n) is the least k > 1 such that the base n representation of k^k ends with that of k.

3, 4, 3, 6, 3, 4, 3, 4, 5, 12, 3, 5, 4, 5, 5, 9, 4, 7, 5, 4, 11, 12, 3, 6, 5, 10, 4, 17, 5, 16, 9, 11, 9, 13, 4, 10, 7, 5, 5, 9, 4, 7, 11, 9, 12, 24, 5, 8, 6, 9, 5, 54, 10, 11, 7, 7, 17, 60, 5, 13, 16, 4, 9, 5, 11, 37, 9, 12, 13, 36, 7, 37, 10, 6, 7, 16, 5, 27

Offset

2,1

Links

Rémy Sigrist, Table of n, a(n) for n = 2..10000

Index entries for sequences related to automorphic numbers

Formula

a(n) <= n+1 with equality iff n belongs to A065296.

Example

a(10) = A082576(2) = 5.

Prog

(PARI) a(n) = for (k=2, oo, if (Mod(k, n^#digits(k, n))^k==k, return (k)))

Crossrefs

Cf. A065296, A082576.

Sequence in context: A332880 A281626 A327650 * A242801 A021295 A061112

Adjacent sequences: A338125 A338126 A338127 * A338129 A338130 A338131

Keyword

nonn,base

Author

Rémy Sigrist, Oct 11 2020

Status

approved