A243473 a(n) = numerator(sigma(n)/n) - denominator(sigma(n)/n) where sigma(n) = sum of divisors of n.
0, 1, 1, 3, 1, 1, 1, 7, 4, 4, 1, 4, 1, 5, 3, 15, 1, 7, 1, 11, 11, 7, 1, 3, 6, 8, 13, 1, 1, 7, 1, 31, 5, 10, 13, 55, 1, 11, 17, 5, 1, 9, 1, 10, 11, 13, 1, 19, 8, 43, 7, 23, 1, 11, 17, 8, 23, 16, 1, 9, 1, 17, 41, 63, 19, 13, 1, 29, 9, 37, 1, 41, 1, 20, 49, 16
Offset: 1
Keywords
Links
- Michel Marcus, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
f[n_] := DivisorSigma[1, n]/n; Table[Numerator[f@ n] - Denominator[f@ n], {n, 76}] (* Michael De Vlieger, Sep 09 2015 *) -
PARI
a(n) = numerator(ab = sigma(n)/n) - denominator(ab);
Comments