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A369453
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Dirichlet inverse of A038548, where A038548 is the number of divisors of n that are at most sqrt(n).
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1
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1, -1, -1, -1, -1, 0, -1, 1, -1, 0, -1, 2, -1, 0, 0, 0, -1, 2, -1, 2, 0, 0, -1, 0, -1, 0, 1, 2, -1, 2, -1, 0, 0, 0, 0, 1, -1, 0, 0, 0, -1, 2, -1, 2, 2, 0, -1, -1, -1, 2, 0, 2, -1, 0, 0, 0, 0, 0, -1, 0, -1, 0, 2, 0, 0, 2, -1, 2, 0, 2, -1, -3, -1, 0, 2, 2, 0, 2, -1, -1, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 2, 0, 0, 0, 0, -1, 2, 2
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OFFSET
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1,12
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LINKS
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FORMULA
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a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A038548(n/d) * a(d).
Dirichlet g.f.: 2/(zeta(s)^2 + zeta(2*s)).
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PROG
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(PARI)
A038548(n) = if( n<1, 0, sumdiv(n, d, d*d <= n))
memoA369453 = Map();
A369453(n) = if(1==n, 1, my(v); if(mapisdefined(memoA369453, n, &v), v, v = -sumdiv(n, d, if(d<n, A038548(n/d)*A369453(d), 0)); mapput(memoA369453, n, v); (v)));
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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