|
|
A280086
|
|
Partial products of A206032 (Product_{d|n} sigma(d)).
|
|
2
|
|
|
1, 3, 12, 252, 1512, 217728, 1741824, 548674560, 28531077120, 9244068986880, 110928827842560, 3130855237028413440, 43831973318397788160, 25247216631397125980160, 14542396779684744564572160, 142006504553621530673047142400, 2556117081965187552114848563200
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
sigma(n) is the sum of the divisors of n (A000203).
|
|
LINKS
|
|
|
FORMULA
|
a(n) = Product_{i=1..n} A206032(i).
|
|
MATHEMATICA
|
FoldList[Times[#1, #2] &, Array[Product[DivisorSigma[1, d], {d, Divisors@ #}] &, 17]] (* 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
|
|
|
STATUS
|
approved
|
|
|
|