A097958 - OEIS

A097958

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

3, 7, 17, 23, 31, 41, 47, 71, 73, 79, 89, 97, 103, 113, 127, 137, 151, 167, 191, 193, 199, 223, 233, 239, 241, 257, 263, 271, 281, 311, 313, 337, 353, 359, 367, 383, 401, 409, 431, 433, 439, 449, 457, 463, 479, 487, 503, 521, 569, 577, 593, 599, 601, 607, 617

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OFFSET

1,1

COMMENTS

Apart from the first term, the same as A001132 or A038873. - Jianing Song, Apr 21 2022

LINKS

Jianing Song, Table of n, a(n) for n = 1..10000 (terms 1..998 from Harvey P. Dale)

FORMULA

Equals {3} union A001132. - Jianing Song, Apr 21 2022

MATHEMATICA

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

PROG

(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", "))) }

(PARI) isA097958(p) = (p==3) || (isprime(p) && kronecker(p, 2)==1) \\ Jianing Song, Apr 21 2022

CROSSREFS

Cf. A001132, A038873.

Sequence in context: A374482 A277213 A152451 * A118940 A127175 A339943

Adjacent sequences: A097955 A097956 A097957 * A097959 A097960 A097961

KEYWORD

nonn,easy

AUTHOR

Cino Hilliard, Sep 06 2004

EXTENSIONS

Definition corrected by Cino Hilliard, Nov 10 2008

Definition clarified by Harvey P. Dale, Dec 25 2021

Offset corrected by Jianing Song, Apr 21 2022

STATUS

approved