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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

Table of n, a(n) for n=1..17.

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

Cf. A000203, A007429, A206032, A280078 (partial products of A007429), A280085 (partial sums of A206032).

Sequence in context: A160320 A321603 A297564 * A102945 A300532 A249940

Adjacent sequences:  A280083 A280084 A280085 * A280087 A280088 A280089

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Dec 26 2016

STATUS

approved

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Last modified May 26 17:40 EDT 2020. Contains 334630 sequences. (Running on oeis4.)