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A082866
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a(1)=1, a(2)=2, otherwise a(n) is the sum of the preceding terms a(j), 1<=j<n, where gcd(n,j)=1.
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1
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1, 2, 3, 4, 10, 11, 31, 45, 93, 128, 328, 370, 1026, 1461, 2898, 4390, 10801, 12197, 33799, 46082, 96616, 145278, 355574, 401570, 1063600, 1563754, 3226314, 4694447, 11660833, 12062393, 35384059, 51835986, 106656033, 158481218, 369773689
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OFFSET
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1,2
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COMMENTS
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It appears that log(a(n))/n approaches a constant, approximately 0.5815, as n -> infinity. - Robert Israel, Aug 05 2014
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LINKS
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EXAMPLE
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a(6)=11 as gcd(6,2)=2, gcd(6,3)=3 and gcd(6,4)=2. So a(6)=a(1)+a(5)=1+10=11.
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MAPLE
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A[1]:= 1: A[2]:= 2:
for n from 3 to 100 do
A[n]:= add(A[j], j=select(t -> igcd(t, n)=1, [$1..n]));
od:
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PROG
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(PARI) { v=vector(100, i, 0); v[1]=1; v[2]=2; print1("1, 2, "); for (i=3, 100, for (j=1, i-1, if (gcd(i, j) == 1, v[i]+=v[j])); print1(v[i]", ")) }
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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