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 A365098 Primes p such that Sum_{k=1..p-1} q^2_p(k) == 0 (mod p), with q_p(k) a Fermat quotient. 0
 2, 11, 971 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The congruence in the definition is given in Gy, 2018, Eq. 16. The terms, except for the prime 2, satisfy the congruence B_{p-1} - 1 + 1/p == (B_{2p-2} - 1 + 1/p)/2 (mod p^2), with B_i a Bernoulli number (cf. Gy, 2018, Eq. 18). Any odd prime that is a term of both A007540 and A197632, i.e., that is simultaneously a Wilson prime and a Lerch prime, is in this sequence (cf. Gy, 2018, Theorem 5). An equivalent definition, better suited for computational purposes, is: "Primes p such that Sum_{k=1..p-1} (k^(p-1) - 1)^2 == 0 (mod p^3)." - John Blythe Dobson, Apr 30 2024 a(4) > 427000, if it exists (Gy, 2018). - Amiram Eldar, Aug 22 2023 a(4) > 39540000, if it exists. - John Blythe Dobson, Apr 30 2024 LINKS Table of n, a(n) for n=1..3. René Gy, Generalized Lerch primes, INTEGERS, 18 (2018), #A10. MATHEMATICA Join[{2}, Select[Prime[Range[2, 200]], Divisible[Numerator[BernoulliB[# - 1] - 1 + 1/# - (BernoulliB[2*# - 2] - 1 + 1/#)/2], #^2] &]] (* Amiram Eldar, Aug 22 2023 *) PROG (PARI) forprime(p = 2, 10000, if(sum(j=1, p-1, (Mod(j, p^3)^(p-1) - 1)^2) % p^3 == 0, print1(p, ", "))) /* John Blythe Dobson, Apr 30 2024 */ CROSSREFS Cf. A007540, A197632. Sequence in context: A092730 A157841 A293240 * A157033 A011825 A306909 Adjacent sequences: A365095 A365096 A365097 * A365099 A365100 A365101 KEYWORD nonn,hard,more,bref AUTHOR Felix Fröhlich, Aug 21 2023 STATUS approved

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Last modified July 17 16:49 EDT 2024. Contains 374377 sequences. (Running on oeis4.)