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 A334214 Odd numbers m such that m^k + 1 is squarefree for all 0 <= k <= (m - 1)/2. 2
 1, 5, 9, 13, 21, 25, 85, 105, 165 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(10) > 10000, if it exists. Most of the relevant factorizations of 165^k+1 were already present in the FactorDB database. The factorization of 165^79+1 has been completed with the software CADO-NFS. - Giovanni Resta, Apr 22 2020 LINKS Table of n, a(n) for n=1..9. PROG (PARI) isOK(m) = k=0; until(k>(m-1)/2, if(!issquarefree(m^k+1), return(0)); k++); 1; for(m=0, 140, if(isOK(m)&&m%2==1, print1(m, ", "))) CROSSREFS Cf. A334212, A334213. Sequence in context: A314792 A089217 A166049 * A053411 A332571 A023382 Adjacent sequences: A334211 A334212 A334213 * A334215 A334216 A334217 KEYWORD nonn,more,hard AUTHOR Gionata Neri, Apr 18 2020 EXTENSIONS a(9) from Giovanni Resta, Apr 22 2020 STATUS approved

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Last modified September 23 21:37 EDT 2023. Contains 365554 sequences. (Running on oeis4.)