A280821 -id:A280821

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Search: a280821 -id:a280821

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A280820

Partial sums of A001783.

+10
1

1, 2, 4, 7, 31, 36, 756, 861, 3101, 3290, 3632090, 3632475, 482634075, 482653380, 483550276, 485577301, 20923275465301, 20923275550386, 6423296981278386, 6423296990008107, 6423344287544107, 6423345537481432, 1124007151123145161432, 1124007151123182343577

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

A001783(n) = the product of totatives of n.

LINKS

Table of n, a(n) for n=1..24.

FORMULA

a(n) = Sum_{i=1..n} A001783(i).

MATHEMATICA

Accumulate@ Table[Times @@ Select[Range@ n, CoprimeQ[n, #] &], {n, 24}] (* Michael De Vlieger, Jan 09 2017 *)

PROG

(Magma) [&+[&*[h: h in [1..k] | GCD(h, k) eq 1]: k in [1..n]]: n in [1..100]]

CROSSREFS

Cf. A001783, A280821.

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jan 08 2017

STATUS

approved

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