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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A180341 a(n) = k is the smallest number such that n is the number of distinct primes dividing k^k + 1. 0

%I #7 Mar 30 2012 18:35:54

%S 0,3,5,9,13,11,18,23,40,30,27,60,35,45,91,69,98,63,119

%N a(n) = k is the smallest number such that n is the number of distinct primes dividing k^k + 1.

%e a(6) = 11 because the 6 distinct primes dividing 11^11 + 1 = 285311670612 are

%e {2, 3, 23, 89, 199, 58367}.

%p with(numtheory):for n from 1 to 8 do:ind:=0:for k from 1 to 40 while(ind=0)

%p do: x:=k^k+1:y:=nops(factorset(x)):if y=n then ind:=1:printf(`%d, `,k):else

%p fi:od: od:

%Y Cf. A014566.

%K nonn,hard

%O 1,2

%A _Michel Lagneau_, Jan 18 2011

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 24 08:09 EDT 2024. Contains 371922 sequences. (Running on oeis4.)