OFFSET
0,4
COMMENTS
Logarithmic transform of A000005.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..470
MAPLE
a:= proc(n) option remember; `if`(n=0, 0, (b-> b(n)-add(a(j)
*binomial(n, j)*j*b(n-j), j=1..n-1)/n)(numtheory[tau]))
end:
seq(a(n), n=0..25); # Alois P. Heinz, Oct 06 2019
MATHEMATICA
nmax = 23; CoefficientList[Series[Log[1 + Sum[DivisorSigma[0, k] x^k/k!, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!
a[n_] := a[n] = DivisorSigma[0, n] - Sum[Binomial[n, k] DivisorSigma[0, n - k] k a[k], {k, 1, n - 1}]/n; a[0] = 0; Table[a[n], {n, 0, 23}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Oct 03 2019
STATUS
approved