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 A281940 Least k such that k^n + 1 is the product of n distinct primes (k > 0). 3
 1, 3, 9, 43, 46, 47, 245, 1697, 109, 565, 3938, 3255, 30089, 18951, 2217 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Corresponding values of k^n + 1 are 2, 10, 730, 3418802, 205962977, 10779215330, ... LINKS Table of n, a(n) for n=1..15. EXAMPLE a(3) = 9 because 9^3 + 1 = 2 * 5 * 73 and 9 is the least number with this property. PROG (PARI) a(n) = my(k=1); while (!issquarefree(k^n+1) || omega(k^n+1) != n, k++); k; CROSSREFS Cf. A001597, A005117, A216765, A280005. Sequence in context: A009584 A013562 A081681 * A141774 A141349 A018427 Adjacent sequences: A281937 A281938 A281939 * A281941 A281942 A281943 KEYWORD nonn,more AUTHOR Altug Alkan, Feb 24 2017 EXTENSIONS a(14)-a(15) from Giovanni Resta, Mar 10 2017 STATUS approved

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Last modified August 5 17:42 EDT 2024. Contains 374953 sequences. (Running on oeis4.)