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Search: id:A076664
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| A076664 |
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a(n) = Sum_{k=1,...,n} antisigma(k), where antisigma(i) = sum of the nondivisors of i that are between 1 and i. |
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+0
1
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| 0, 0, 2, 5, 14, 23, 43, 64, 96, 133, 187, 237, 314, 395, 491, 596, 731, 863, 1033, 1201, 1400, 1617, 1869, 2109, 2403, 2712, 3050, 3400, 3805, 4198, 4662, 5127, 5640, 6181, 6763, 7338, 8003, 8684, 9408, 10138, 10957, 11764, 12666, 13572, 14529, 15538
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OFFSET
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1,3
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EXAMPLE
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a(5) = antisigma(1) + ... + antisigma(5) = 0 + 0 + 2 + 3 + 9 = 14.
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MATHEMATICA
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l = {}; s = 0; Do[s = s + (n (n + 1) / 2) - DivisorSigma[1, n]; l = Append[l, s], {n, 1, 100}]; l
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CROSSREFS
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Sequence in context: A118670 A015633 A131661 this_sequence A049939 A133375 A057295
Adjacent sequences: A076661 A076662 A076663 this_sequence A076665 A076666 A076667
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 24 2002
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