A199858 Decimal expansion of Sum_{n = 1 .. infinity }[ 1 / Sum {i = 1 .. m} d(i)^n] where d(i) are the divisors of n and m = tau(n) is the number of divisors of n.

1, 2, 3, 9, 7, 1, 9, 5, 3, 8, 1, 4, 6, 2, 2, 7, 4, 1, 1, 9, 6, 5, 0, 4, 2, 6, 7, 6, 5, 2, 4, 5, 8, 7, 1, 0, 4, 6, 7, 9, 0, 0, 0, 3, 6, 4, 6, 2, 3, 5, 4, 2, 7, 4, 1, 4, 2, 9, 5, 8, 6, 3, 0, 5, 7, 6, 9, 8, 9, 8, 3, 3, 8, 1, 7, 1, 7, 6, 5, 2, 1, 5, 0, 9, 6, 0, 2, 6, 2, 4, 8, 4, 8, 9, 7, 7, 1, 1, 4, 7, 6, 8, 7, 0, 3

Offset

1,2

Links

Table of n, a(n) for n=1..105.

Example

1.23971953814622741196504267652458710467...

Mathematica

RealDigits[N[Sum[1/DivisorSigma[n, n], {n, 1, 100}], 130]][[1]]

Crossrefs

Sequence in context: A288842 A108694 A267896 * A357053 A340442 A199963

Adjacent sequences: A199855 A199856 A199857 * A199859 A199860 A199861

Keyword

nonn,cons

Author

Michel Lagneau, Nov 28 2011

Status

approved