cp's OEIS Frontend

A162252 Numbers of the form prime(prime(prime(k))) with a digit sum which is prime.

%I A162252 #9 Nov 02 2014 18:22:39
%S A162252 5,11,179,331,599,919,1297,1523,1787,2221,3259,3637,3943,4397,5381,
%T A162252 6113,6661,6823,8221,9859,10631,11953,12097,12301,12547,12763,13469,
%U A162252 14723,15641,15823,17627,18149,19577,20063,20773,21529,23431,26371,26489
%N A162252 Numbers of the form prime(prime(prime(k))) with a digit sum which is prime.
%C A162252 Members of A038580 with a digit sum which is prime.
%F A162252 {A038508(k): A007953(A038508(k)) in A000040, any k}.
%e A162252 For k=6, prime(prime(prime(6))) = A038580(6)=179. The digit sum 1+7+9 = 17 is prime, so 179 is in the sequence.
%p A162252 read("transforms") ; A038580 := proc(n) ithprime(ithprime(ithprime(n))) ; end:
%p A162252 for n from 1 to 80 do if isprime(digsum(A038580(n))) then printf("%d,", A038580(n)) ; fi; od: # _R. J. Mathar_, Aug 14 2009
%t A162252 Select[Table[Nest[Prime, x, 3], {x, 1, 100}],
%t A162252 PrimeQ[Total[IntegerDigits[#, 10]]] &]
%o A162252 (PARI) sodip2(n,m) = /* m multiple nesting of prime(prime(prime..(n) */
%o A162252 { local(s=0,a,x,y,j,p);
%o A162252 for(x=1,n, p=prime(x);
%o A162252 for(i=1,m,p=prime(p));
%o A162252 a=eval(Vec(Str(p))); y=sum(j=1,length(a),a[j]); if(isprime(y),print1(p","));)
%o A162252 }
%K A162252 nonn,base
%O A162252 1,1
%A A162252 _Cino Hilliard_, Jun 28 2009
%E A162252 Edited by _R. J. Mathar_, Aug 14 2009