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A317964
Prime numbers in the lexicographically earliest sequence of positive integers whose prime indices are not already in the sequence (A304360).
2
2, 5, 13, 17, 23, 31, 37, 43, 47, 61, 67, 73, 79, 89, 103, 107, 109, 113, 137, 149, 151, 163, 167, 179, 181, 193, 197, 223, 227, 233, 241, 251, 257, 263, 269, 271, 277, 281, 307, 317, 347, 349, 353, 359, 379, 383, 389, 397, 419, 421, 431, 433, 449, 457, 463, 467, 487, 499, 503, 509, 521, 523, 547
OFFSET
1,1
COMMENTS
Also primes whose prime index is not in A304360, or is in A324696. A prime index of n is a number m such that prime(m) divides n. - Gus Wiseman, Mar 19 2019
LINKS
MAPLE
count:= 0:
P:= {}: A:= NULL:
for n from 2 while count < 100 do
pn:= numtheory:-factorset(n);
if pn intersect P = {} then
P:= P union {ithprime(n)};
if isprime(n) then A:= A, n; count:= count+1 fi;
fi
od:
A; # Robert Israel, Aug 26 2018
MATHEMATICA
aQ[n_]:=n==1||Or@@Cases[FactorInteger[n], {p_, _}:>!aQ[PrimePi[p]]];
Prime[Select[Range[100], aQ]] (* Gus Wiseman, Mar 19 2019 *)
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Aug 26 2018
STATUS
approved