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A215141
Decimal expansion of Sum_{n>=1} (-1)^(n+1) / sigma(n)^n.
2
9, 0, 4, 2, 2, 6, 1, 3, 8, 2, 2, 8, 4, 3, 4, 5, 2, 1, 1, 4, 6, 2, 7, 4, 9, 6, 5, 6, 2, 5, 6, 5, 6, 2, 7, 3, 2, 8, 7, 5, 1, 8, 2, 8, 3, 4, 9, 0, 3, 8, 1, 7, 6, 7, 3, 5, 9, 9, 7, 9, 1, 0, 9, 8, 7, 5, 8, 3, 2, 8, 2, 4, 3, 4, 7, 8, 8, 1, 4, 3, 0, 3, 6, 0, 5, 6, 8
OFFSET
0,1
LINKS
EXAMPLE
.90422613822843452114627...
MATHEMATICA
RealDigits[N[Sum[((-1)^(n+1))/DivisorSigma[1, n]^n, {n, 1, 105}], 105]][[1]]
PROG
(PARI) suminf(n=1, (-1)^(n+1)/sigma(n)^n) \\ Michel Marcus, Apr 20 2018
CROSSREFS
Sequence in context: A154705 A197389 A086307 * A248951 A198226 A195692
KEYWORD
nonn,cons
AUTHOR
Michel Lagneau, Aug 04 2012
STATUS
approved