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Search: id:A064948
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| A064948 |
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Sum_{i|n, j|n} max(i,j). |
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+0
1
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| 1, 7, 10, 27, 16, 64, 22, 83, 55, 102, 34, 236, 40, 140, 140, 227, 52, 343, 58, 372, 192, 216, 70, 708, 141, 254, 244, 510, 88, 866, 94, 579, 296, 330, 296, 1241, 112, 368, 348, 1104, 124, 1184, 130, 786, 728, 444, 142, 1908, 267, 877, 452, 924, 160, 1504, 456
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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FORMULA
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a(n) = Sum_{i=1..tau(n)} (2*i-1)*d_i, where {d_i}, i=1..tau(n), is increasing sequence of divisors of n.
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EXAMPLE
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a(6) = dot_product(1,3,5,7)*(1,2,3,6)=1*1+3*2+5*3+7*6=64.
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MAPLE
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with(numtheory): seq(add((2*i-1)*sort(convert(divisors(n), 'list'))[i], i=1..tau(n)), n=1..200);
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PROGRAM
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(PARI) { for (n=1, 1000, d=divisors(n); a=sum(i=1, length(d), (2*i - 1)*d[i]); write("b064948.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 01 2009]
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CROSSREFS
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Cf. A000005, A000203.
Sequence in context: A103119 A054224 A134329 this_sequence A064950 A058532 A070422
Adjacent sequences: A064945 A064946 A064947 this_sequence A064949 A064950 A064951
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KEYWORD
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nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 28 2001
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