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 A113571 Let H(n) be the reduced fraction Sum_{i=1..n} 1/i. a(n) is the least factor of H(n)'s numerator or denominator that doesn't divide either part of any earlier H(m). 0
 1, 2, 6, 4, 10, 7, 14, 8, 9, 61, 22, 13, 26, 1049, 41233, 16, 34, 19, 38, 11167027, 18858053, 23, 46, 138, 50, 34395742267, 27, 841, 58, 31, 62, 32, 269, 3583, 397, 1297, 74, 199, 737281, 41, 82, 301, 86, 407, 1553, 47, 94, 2323031, 98, 587948341, 76943, 2809, 106, 5953, 51862596437, 252476961434436524654789, 26693, 59, 118, 2207, 122, 928551009361054917576341971, 347, 64, 2473, 67, 134 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Also, a(n) is the first occurrence of n in A110545. Conjectured last occurrence of n: 1,3,11,25,137,49,363,761,7129,7381,83711, [sic] 6617,72072,1117 (is this A001008?) LINKS MATHEMATICA f[n_] := f[n] = Block[{h = k = 1}, While[ !IntegerQ[ Numerator[h]/n] && ! IntegerQ[Denominator[h]/n], k++; h = h + 1/k]; k]; Do[ f[n], {n, 84000}]; Table[ Select[ Range[84000], f[ # ] == n &][[1]], {n, 60}] CROSSREFS Cf. A110545, A001008. Sequence in context: A238642 A145019 A066678 * A119018 A264647 A094748 Adjacent sequences:  A113568 A113569 A113570 * A113572 A113573 A113574 KEYWORD nonn AUTHOR Leroy Quet and Robert G. Wilson v, Sep 29 2005 EXTENSIONS Entry revised (better definition, corrections, more terms) by Don Reble, Aug 14 2014 STATUS approved

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Last modified October 17 12:01 EDT 2018. Contains 316279 sequences. (Running on oeis4.)