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Search: id:A110794
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| A110794 |
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a(1)=1. a(n) = sum{k=1 to n-1}(number of divisors of a(k) which also divide n). |
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+0
1
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| 1, 1, 2, 4, 4, 8, 6, 16, 9, 15, 10, 26, 13, 21, 21, 30, 16, 36, 18, 42, 35, 34, 22, 62, 28, 45, 40, 61, 28, 76, 31, 67, 43, 55, 48, 93, 36, 61, 53, 90, 40, 100, 43, 85, 81, 70, 46, 125, 55, 100, 67, 97, 53, 116, 74, 120, 73, 90, 58, 183, 63, 98, 104, 127, 84, 136, 68, 135, 90
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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The divisors of the first 5 terms of the sequence are: a(1):1; a(2):1; a(3):1,2; a(4):1,2,4; a(5):1,2,4. Eight of these divisors divide 6. (These divisors are 1;1;1,2;1,2;1,2.) So a(6) = 8.
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MATHEMATICA
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a = {1}; Do[AppendTo[a, Sum[Length[Select[Divisors[a[[i]]], Mod[Length[a] + 1, # ] == 0 &]], {i, 1, Length[a]}]], {70}]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Oct 16 2007
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CROSSREFS
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Sequence in context: A079890 A065608 A077764 this_sequence A117295 A093820 A095400
Adjacent sequences: A110791 A110792 A110793 this_sequence A110795 A110796 A110797
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Apr 26 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Oct 16 2007
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