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A119993
a(n) = n-th prime from among those primes which are coprime to n.
4
2, 5, 7, 11, 13, 19, 19, 23, 29, 37, 37, 43, 43, 53, 59, 59, 61, 71, 71, 79, 83, 89, 89, 101, 101, 107, 107, 113, 113, 137, 131, 137, 149, 151, 157, 163, 163, 173, 179, 181, 181, 197, 193, 199, 211, 223, 223, 229, 229, 239, 241, 251, 251, 263, 269, 271, 277, 281
OFFSET
1,1
LINKS
FORMULA
a(n) = A000040(n + A001221(n)). - Jon Maiga, Jan 05 2019
EXAMPLE
5,7,11,13,17,19,23,... is the sequence of primes which are coprime to 6. 19 is the 6th such prime, so a(6) = 19.
MAPLE
f:= n -> ithprime(n + nops(numtheory:-factorset(n)));
map(f, [$1..100]); # Robert Israel, Sep 28 2023
MATHEMATICA
With[{prs=Prime[Range[1000]]}, Table[Select[prs, CoprimeQ[#, n]&][[n]], {n, 60}]] (* Harvey P. Dale, Aug 27 2014 *)
Table[Prime[n + PrimeNu[n]], {n, 60}] (* Jon Maiga, Jan 05 2019 *)
PROG
(PARI) {m=59; for(n=1, m, q=2; k=n; while(k>0, p=q; if(gcd(p, n)==1, k--); q=nextprime(p+1)); print1(p, ", "))} \\ Klaus Brockhaus, Aug 15 2006
CROSSREFS
Sequence in context: A265809 A303112 A182320 * A045346 A039675 A074833
KEYWORD
nonn
AUTHOR
Leroy Quet, Aug 03 2006
EXTENSIONS
More terms from Klaus Brockhaus, Aug 15 2006
STATUS
approved