A199858 - OEIS

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.

%I #19 Mar 30 2012 18:36:00

%S 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,

%T 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,

%U 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

%N 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.

%e 1.23971953814622741196504267652458710467...

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

%K nonn,cons

%O 1,2

%A _Michel Lagneau_, Nov 28 2011