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Search: id:A122142
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| A122142 |
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Numbers n such that n divides A122103[n] = Sum[ Prime[k]^5, {k,1,n} ]. |
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+0
20
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OFFSET
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1,2
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COMMENT
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No other terms up to 10^8. -Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 06 2007
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EXAMPLE
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a(2) = 25 because 25 is the first number n>1 that divides A122103[n] = Sum[ Prime[k]^5, {k,1,n} ].
Mod[ A122103[25], 25] = Mod[ 2^5 + 3^5 + 5^5 + ... + 89^5 + 97^5, 25 ] = 0.
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MATHEMATICA
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s = 0; t = {}; Do[s = s + Prime[n]^5; If[ Mod[s, n] == 0, AppendTo[t, n]], {n, 1000000}]; t
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CROSSREFS
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Cf. A122103, A098999, A007504, A045345, A024450, A111441, A122102, A122140.
Sequence in context: A012835 A132540 A142998 this_sequence A151557 A008844 A159332
Adjacent sequences: A122139 A122140 A122141 this_sequence A122143 A122144 A122145
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KEYWORD
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nonn,hard
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Aug 21 2006
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EXTENSIONS
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2 more terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 06 2007
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