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0, 1, 1, 3, 1, 4, 1, 4, 3, 11, 1, 3, 1, 16, 4, 16, 1, 5, 1, 4, 11, 46, 1, 8, 3, 82, 4, 27, 1, 10, 1, 8, 16, 174, 4, 20, 1, 256, 46, 32, 1, 4, 1, 17, 3, 798, 1, 8, 3, 15, 82, 45, 1, 12, 11, 20, 174, 1300, 1, 2, 1, 2734, 4, 72, 16, 27, 1, 125, 256, 8, 1, 20, 1, 4354, 5, 363, 4, 25, 1, 8, 16, 10926, 1, 53, 46, 20518, 798, 168, 1, 35, 11, 317
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OFFSET
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1,4
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COMMENTS
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The first three zeros after a(1) occur at n = 192, 288, 3645.
The first negative term is a(150) = -1. There are 184 negative terms among the first 4473 terms.
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LINKS
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FORMULA
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PROG
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(PARI)
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
memoA324118 = Map();
A324118(n) = if(1==n, 0, my(v); if(mapisdefined(memoA324118, n, &v), v, v=sigma(A322993(n)); mapput(memoA324118, 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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