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%I #13 Jun 19 2018 05:17:12
%S 0,1,1,4,1,10,1,11,5,12,1,36,1,14,14,26,1,43,1,45,16,18,1,96,7,20,18,
%T 53,1,107,1,57,20,24,20,153,1,26,22,123,1,128,1,69,65,30,1,224,9,73,
%U 26,77,1,148,24,147,28,36,1,374,1,38,77,120,26,168,1,93,32,165,1,411,1,44
%N a(n) = Sum_{i|n, j|n, j>i} i.
%C For given n, iterate a(n); a(a(n)); a(a(a(n))); ... Does this iterative process always lead to a(a(...(a(n))...) = 1? - _Ctibor O. Zizka_, Apr 17 2008
%H Harry J. Smith, <a href="/A064947/b064947.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = Sum_{i=1..tau(n)} (tau(n)-i)*d_i, where {d_i}, i=1..tau(n), is increasing sequence of divisors of n.
%e a(6) = dot_product(3,2,1,0)*(1,2,3,6) = 3*1 + 2*2 + 1*3 + 0*6 = 10.
%p with(numtheory): seq(add((tau(n)-i)*sort(convert(divisors(n),'list'))[i],i=1..tau(n)), n=1..200);
%o (PARI) { for (n=1, 1000, d=divisors(n); t=length(d); a=sum(i=1, t - 1, (t - i)*d[i]); write("b064947.txt", n, " ", a) ) } \\ _Harry J. Smith_, Oct 01 2009
%Y Cf. A000005, A000203.
%K nonn
%O 1,4
%A _Vladeta Jovovic_, Oct 28 2001
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