A386913 Smallest k for which the number of divisors d of k such that d == -d^k (mod k) is equal to n, or -1 if no such k exists.

1, 2, 6, 42, 66, 1770, 2926, 8646, 178486, 90706, 639730, 17646706, 5533066, 35193246, 13775230, 144313246

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Prog

(Magma) [Min([k: k in [1..2*10^5] | 1 + #[d: d in Divisors(k) | -Modexp(d, k, k) mod k eq d] eq n]): n in [1..10]];

Crossrefs

Cf. A032741, A371513, A380393, A380656.

Sequence in context: A309813 A033936 A380393 * A385499 A203618 A334883

Adjacent sequences: A386910 A386911 A386912 * A386914 A386915 A386916

Keyword

nonn,more

Author

Juri-Stepan Gerasimov, Sep 05 2025

Status

approved