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A359779
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Dirichlet inverse of A359778, where A359778 is the number of factorizations of n into factors not divisible by p^p for any prime p (terms of A048103).
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2
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1, -1, -1, 0, -1, 0, -1, 0, -1, 0, -1, 1, -1, 0, 0, 0, -1, 1, -1, 1, 0, 0, -1, 0, -1, 0, 1, 1, -1, 1, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, -1, 1, -1, 1, 1, 0, -1, 0, -1, 1, 0, 1, -1, 1, 0, 0, 0, 0, -1, 0, -1, 0, 1, 0, 0, 1, -1, 1, 0, 1, -1, 0, -1, 0, 1, 1, 0, 1, -1, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 1, 0, 1, 0, 0, 0, 0, -1, 1, 1, 0, -1, 1, -1, 0, 1
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OFFSET
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1,420
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COMMENTS
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The first term with absolute value larger than 1 is a(420) = -2.
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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} A359778(n/d) * a(d).
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PROG
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(PARI)
A359550(n) = { my(f = factor(n)); prod(k=1, #f~, (f[k, 1]>f[k, 2])); };
A359778(n, m=n) = if(1==n, 1, my(s=0); fordiv(n, d, if((d>1) && (d<=m) &&
memoA359779 = Map();
A359779(n) = if(1==n, 1, my(v); if(mapisdefined(memoA359779, n, &v), v, v = -sumdiv(n, d, if(d<n, A359778(n/d)*A359779(d), 0)); mapput(memoA359779, 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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