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Search: id:A064946
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| 0, 2, 3, 10, 5, 26, 7, 34, 21, 42, 11, 104, 13, 58, 58, 98, 17, 152, 19, 165, 80, 90, 23, 324, 55, 106, 102, 227, 29, 397, 31, 258, 124, 138, 124, 575, 37, 154, 146, 507, 41, 544, 43, 351, 325, 186, 47, 892, 105, 392, 190, 413, 53, 692, 192, 693, 212, 234, 59
(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)} (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(0,1,2,3)*(1,2,3,6)=0*1+1*2+2*3+3*6=26.
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MAPLE
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with(numtheory): seq(add((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=2, length(d), (i - 1)*d[i]); write("b064946.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: A048985 A112417 A139693 this_sequence A078730 A163767 A128531
Adjacent sequences: A064943 A064944 A064945 this_sequence A064947 A064948 A064949
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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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