The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A275211 Numbers of the form p^^k, where p is prime, k > 1, and ^^ is the tetration operator: x^^y = x^x^...^x with y copies of x. 2

%I #9 Jul 20 2016 10:46:49

%S 4,16,27,3125,65536,823543,285311670611,7625597484987,302875106592253,

%T 827240261886336764177,1978419655660313589123979,

%U 20880467999847912034355032910567

%N Numbers of the form p^^k, where p is prime, k > 1, and ^^ is the tetration operator: x^^y = x^x^...^x with y copies of x.

%H Charles R Greathouse IV, <a href="/A275211/b275211.txt">Table of n, a(n) for n = 1..79</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Tetration">Tetration</a>

%F For any prime number, p, p tetrated x times, where x is any integer greater than 1, is a prime tetration.

%e a(1) = 2^^2 = 2^2 = 4.

%e a(2) = 2^^3 = 2^2^2 = 16.

%e a(3) = 3^^2 = 3^3 = 27.

%e a(4) = 5^^2 = 5^5 = 3125.

%o tetr(b,n)=my(t=b); for(i=2,n, t=b^t); t

%o list(lim)=my(v=List(),p,t); for(k=2,slogint(lim\=1,2), p=1; while(tetr(1.0 * p=nextprime(p+1),k) <= 2*lim, listput(v,tetr(p,k)))); select(n->n<=lim, Set(v)) \\ _Charles R Greathouse IV_, Jul 19 2016

%o (PARI) is(n)=my(p,e); e=isprimepower(n,&p); e && (e==p || (e%p==0 && is(e))) \\ _Charles R Greathouse IV_, Jul 19 2016

%Y Cf. A000040.

%K nonn

%O 1,1

%A _Tyler Skywalker_, Jul 19 2016

%E a(5) inserted, a(10)-a(12) corrected by _Charles R Greathouse IV_, Jul 19 2016

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.

Last modified May 18 03:12 EDT 2024. Contains 372617 sequences. (Running on oeis4.)