The OEIS is supported by the many generous donors to the OEIS Foundation.

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

1

`%I #19 Feb 25 2019 20:32:23
`

`%S 1,1365,6946975,160559525,324148475
`

`%N Odd numbers k such that 2^d(k) == d(k) (mod k).
`

`%H Robert Israel, <a href="/A292780/a292780.txt">51 terms of the sequence</a> (it is possible that this list is missing some terms, so it is not a b-file)
`

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

`%o (PARI) isok(n) = (n%2==1) && (dn=numdiv(n)) && (Mod(2, n)^dn == dn); \\ _Michel Marcus_, Feb 25 2019
`

`%Y Cf. A000005.
`

`%K nonn,more
`

`%O 1,2
`

`%A _Altug Alkan_, Sep 23 2017
`