OFFSET
1,2
COMMENTS
sigma(n) is the sum of the divisors of n (A000203).
FORMULA
a(n) = Sum_{i=1..n} A206032(i).
MATHEMATICA
Accumulate@ Array[Product[DivisorSigma[1, d], {d, Divisors@ #}] &, 35] (* Michael De Vlieger, Dec 26 2016 *)
PROG
(Magma) [&+[&*[SumOfDivisors(d): d in Divisors(k)]: k in [1..n]]: n in [1..100]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Dec 26 2016
STATUS
approved