A240942 Numbers k that divide 2^k + 9.

1, 11, 121, 323, 117283, 432091, 4132384531, 15516834659, 15941429747, 98953554491, 3272831195051, 7362974489179, 26306805687881, 33869035218491, 280980898827691

Offset: 1

Author

Derek Orr, Aug 04 2014

Keywords

• nonn
• more
• hard

Comments

No other terms below 10^15. Some larger terms: 53496121130110340001650284048539458491, 136243118444105327963550175410279542214992801356720577. - Max Alekseyev, Sep 29 2016

Examples

			2^11 + 9 = 2057 is divisible by 11. Thus 11 is a term of this sequence.
		

Links

• OEIS Wiki, 2^n mod n

Crossrefs

Cf. A051447, A188165, A245594, A245319, A245318, A244673.

Programs

Maple

select(n -> 9 + 2 &^ n mod n = 0, [$1..10^6]); # Robert Israel, Aug 04 2014

PARI

for(n=1,10^9, if(Mod(2,n)^n==-9, print1(n,", "); ); );

Extensions

a(7)-a(10) from Lars Blomberg, Nov 05 2014

a(11)-a(15) from Max Alekseyev, Sep 29 2016