A191042 - OEIS

%I #12 Sep 08 2022 08:45:57

%S 5,11,13,17,31,53,73,83,89,107,113,127,137,139,149,151,163,191,193,

%T 211,223,227,251,263,271,277,281,293,307,331,349,359,383,389,397,401,

%U 409,419,431,439,463,467,479,487,499,503,521,541,547,557,563,569,577,601

%N Primes p that have Jacobi symbol (p|69) = 1.

%C Originally incorrectly named "primes which are squares mod 69", which would be the sequence (3, 13, 31, 73, 127, 139, 151, 163, 193, 211, 223, 271, 277, 307, 331, 349, 397, ...). - _M. F. Hasler_, Jan 15 2016

%H Vincenzo Librandi, <a href="/A191042/b191042.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime[Range[200]], JacobiSymbol[#,69]==1&]

%o (Magma) [p: p in PrimesUpTo(601) | JacobiSymbol(p, 69) eq 1]; // _Vincenzo Librandi_, Sep 10 2012

%o (PARI) select(p->kronecker(p, 69)==1&&isprime(p), [1..1000]) \\ This is to provide a generic characteristic function ("is_A191043") as 1st arg of select(), there are other ways to produce the sequence more efficiently. - _M. F. Hasler_, Jan 15 2016

%Y Cf. A191017, A191018, A191020, A191023, A191025, A191026, A191028, A191029, A191032, A191034, A191036, A191037, A191040, A191043, A191046, A191047, A191049.

%K nonn,easy

%O 1,1

%A _T. D. Noe_, May 25 2011

%E Definition corrected (following an observation by _David Broadhurst_) by _M. F. Hasler_, Jan 15 2016