|
| |
|
|
A162252
|
|
Numbers of the form prime(prime(prime(k))) with a digit sum which is prime.
|
|
0
|
|
|
|
5, 11, 179, 331, 599, 919, 1297, 1523, 1787, 2221, 3259, 3637, 3943, 4397, 5381, 6113, 6661, 6823, 8221, 9859, 10631, 11953, 12097, 12301, 12547, 12763, 13469, 14723, 15641, 15823, 17627, 18149, 19577, 20063, 20773, 21529, 23431, 26371, 26489
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Members of A038580 with a digit sum which is prime.
|
|
|
LINKS
|
|
|
|
FORMULA
|
|
|
|
EXAMPLE
|
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.
|
|
|
MAPLE
|
read("transforms") ; A038580 := proc(n) ithprime(ithprime(ithprime(n))) ; end:
|
|
|
MATHEMATICA
|
Select[Table[Nest[Prime, x, 3], {x, 1, 100}],
PrimeQ[Total[IntegerDigits[#, 10]]] &]
|
|
|
PROG
|
(PARI) sodip2(n, m) = /* m multiple nesting of prime(prime(prime..(n) */
{ local(s=0, a, x, y, j, p);
for(x=1, n, p=prime(x);
for(i=1, m, p=prime(p));
a=eval(Vec(Str(p))); y=sum(j=1, length(a), a[j]); if(isprime(y), print1(p", ")); )
}
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn,base
|
|
|
AUTHOR
|
|
|
|
EXTENSIONS
|
|
|
|
STATUS
|
approved
|
| |
|
|
