A292780 Odd numbers k such that 2^d(k) == d(k) (mod k).

1, 1365, 6946975, 160559525, 324148475

Offset

1,2

Links

Table of n, a(n) for n=1..5.

Robert Israel, 51 terms of the sequence (it is possible that this list is missing some terms, so it is not a b-file)

Example

1365 = 3*5*7*13 is a term because d(1365) = 2^4 and 2^16 == 16 (mod 3*5*7*13).

Prog

(PARI) isok(n) = (n%2==1) && (dn=numdiv(n)) && (Mod(2, n)^dn == dn); \\ Michel Marcus, Feb 25 2019

Crossrefs

Cf. A000005.

Sequence in context: A022204 A015405 A295466 * A180089 A020409 A231268

Adjacent sequences: A292777 A292778 A292779 * A292781 A292782 A292783

Keyword

nonn,more

Author

Altug Alkan, Sep 23 2017

Status

approved