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Primes p such that p divides 6^((p-1)/2) - 3^((p-1)/2).
2

%I #20 Apr 21 2022 09:18:20

%S 3,7,17,23,31,41,47,71,73,79,89,97,103,113,127,137,151,167,191,193,

%T 199,223,233,239,241,257,263,271,281,311,313,337,353,359,367,383,401,

%U 409,431,433,439,449,457,463,479,487,503,521,569,577,593,599,601,607,617

%N Primes p such that p divides 6^((p-1)/2) - 3^((p-1)/2).

%C Apart from the first term, the same as A001132 or A038873. - _Jianing Song_, Apr 21 2022

%H Jianing Song, <a href="/A097958/b097958.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..998 from Harvey P. Dale)

%F Equals {3} union A001132. - _Jianing Song_, Apr 21 2022

%t Select[Prime[Range[150]],Divisible[6^((#-1)/2)-3^((#-1)/2),#]&] (* _Harvey P. Dale_, Dec 25 2021 *)

%o (PARI) \s = +-1,d=diff ptopm1d2(n,x,d,s) = { forprime(p=3,n,p2=(p-1)/2; y=x^p2 + s*(x-d)^p2; if(y%p==0,print1(p","))) }

%o (PARI) isA097958(p) = (p==3) || (isprime(p) && kronecker(p,2)==1) \\ _Jianing Song_, Apr 21 2022

%Y Cf. A001132, A038873.

%K nonn,easy

%O 1,1

%A _Cino Hilliard_, Sep 06 2004

%E Definition corrected by _Cino Hilliard_, Nov 10 2008

%E Definition clarified by _Harvey P. Dale_, Dec 25 2021

%E Offset corrected by _Jianing Song_, Apr 21 2022