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A326227
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Indices of nonsquarefree numerators (A001008) of harmonic numbers H(n) = Sum_{k=1..n} 1/k.
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0
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4, 6, 7, 10, 12, 16, 18, 22, 28, 29, 30, 36, 40, 42, 46, 52, 58, 60, 66, 70, 72, 78, 82, 88, 96, 100, 102, 106, 108, 112, 126, 130, 136, 138, 148, 150, 156, 162, 166, 172, 178, 180, 190, 192, 196, 198, 210, 222, 226, 228, 232, 238, 240, 250, 256, 262, 268, 270, 276
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OFFSET
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1,1
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COMMENTS
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It appears that the first term of A001008 having a cubic factor is A001008(848) = 11^3 * 1871 * C359.
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LINKS
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PROG
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(PARI) is_A326227(n)={n>3&&vecmax(factor(A001008(n))[, 2])>1} \\ Add , 0 in factor() for much faster but possibly incorrect results [false negative].
for(n=1, oo, is_A326227(n) && print1(n", "))
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CROSSREFS
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KEYWORD
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nonn,more,hard
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AUTHOR
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STATUS
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approved
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