The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A046431 Sum of digits of a(n) raised to its digits powers is prime. 11

%I

%S 10,11,12,14,20,21,23,27,32,34,40,41,43,47,72,74,100,101,103,110,111,

%T 113,130,131,157,175,236,263,289,298,300,301,310,311,326,348,355,362,

%U 384,438,445,454,458,483,485,507,517,535,544,548,553,570,571,584,623

%N Sum of digits of a(n) raised to its digits powers is prime.

%C If p is prime, then R_p (see A002275) is a term, so the sequence is infinite. - _Marius A. Burtea_, Sep 18 2019

%H Marius A. Burtea, <a href="/A046431/b046431.txt">Table of n, a(n) for n = 0..5000</a>

%e 10 is a term: 10 -> 1^1 + 0^0 = 2 (prime).

%e 289 is a term: 289 -> 2^2 + 8^8 + 9^9 = 404197709 (prime).

%p q:= n-> (l-> isprime(add(i^i, i=l)))(convert(n, base, 10)):

%p select(q, [\$0..1000])[]; # _Alois P. Heinz_, Sep 18 2019

%t sopQ[n_] := PrimeQ[Total[#^# & /@ (IntegerDigits[n] /. {0 -> 1})]]; Select[Range[625], sopQ[#] &] (* _Jayanta Basu_, Jun 25 2013 *)

%o (MAGMA) [k:k in [1..650]| IsPrime( &+[a[s]^(a[s]): s in [1..# a]]) where a is Intseq(k) ]; // _Marius A. Burtea_, Sep 18 2019

%Y Cf. A046432-A046441.

%K nonn,base

%O 0,1

%A _Patrick De Geest_, Jul 15 1998

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

Last modified July 28 19:33 EDT 2021. Contains 346335 sequences. (Running on oeis4.)