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Numbers k whose generalized Wilson quotient A157249(k) is prime.
1

%I #27 Mar 22 2023 04:29:05

%S 1,5,7,8,10,11,29,62,486,614,773,1321,1906,2621

%N Numbers k whose generalized Wilson quotient A157249(k) is prime.

%C The corresponding primes are 2, 5, 103, 13, 19, 329891, ...

%C Supersequence of A050299 (except for 1, the prime terms of this sequence).

%C No more terms below 10^4.

%t p[n_] := Times @@ Select[Range[n], CoprimeQ[n, #] &]; e[1 | 2 | 4] = 1; e[n_] := (fi = FactorInteger[n]; If[MatchQ[fi, {{(p_)?OddQ, _}} | {{2, 1}, {_, _}}], 1, -1]); a[n_] := (p[n] + e[n])/n; n = 1; s={}; Do[If[PrimeQ[a[n]], AppendTo[s,n]], {n, 1, 1000}]; s (* after _Jean-François Alcover_ at A157249 *)

%o (PARI) phito(n) = prod(k=2, n-1, k^(gcd(k, n)==1)); \\ A001783

%o is(n) = if(n%2, isprimepower(n) || n==1, n==2 || n==4 || (isprimepower(n/2, &n) && n>2)); \\ A033948

%o e(n) = if (is(n), 1, -1);

%o gw(n) = (phito(n)+e(n))/n;

%o isok(n) = isprime(gw(n)); \\ _Michel Marcus_, Oct 28 2018

%Y Cf. A007619, A050299, A157249.

%K nonn,more

%O 1,2

%A _Amiram Eldar_, Sep 29 2018