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 A124391 Numbers n that divide A123269(n) = Sum[ i^j^k, {i,1,n}, {j,1,n}, {k,1,n} ]. 2
 1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 14, 16, 18, 20, 21, 22, 23, 24, 27, 28, 31, 32, 33, 36, 40, 42, 43, 44, 46, 47, 48, 49, 54, 56, 59, 60, 62, 63, 64, 66, 67, 69, 71, 72, 77, 79, 80, 81, 83, 84, 86, 88, 92, 93, 94, 96, 98, 99, 100, 103 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A123269(n) = Sum[ i^j^k, {i,1,n}, {j,1,n}, {k,1,n} ] = {1, 28, 7625731729896, ...}. Primes in a(n) are {2, 3, 7, 11, 23, 31, 43, 47, 59, 67, 71, 79, 83, 103, ...} = A039787(n) Primes p such that p-1 is squarefree. LINKS MATHEMATICA Do[f=Sum[Mod[Sum[Mod[Sum[PowerMod[i, j^k, n], {i, 1, n}], n], {j, 1, n}], n], {k, 1, n}]; If[IntegerQ[f/n], Print[n]], {n, 1, 103}] CROSSREFS Cf. A123269, A039787, A086787. Sequence in context: A268377 A201010 A004144 * A200381 A050118 A081754 Adjacent sequences:  A124388 A124389 A124390 * A124392 A124393 A124394 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Oct 30 2006 STATUS approved

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Last modified October 19 02:41 EDT 2019. Contains 328211 sequences. (Running on oeis4.)