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 A280133 Partial products of A057661 (Sum_{d|n} psi(d)). 1
 1, 2, 8, 48, 528, 5808, 127776, 2811072, 87143232, 2788583424, 156160671744, 6090266198016, 481131029643264, 31273516926812160, 2314240252584099840, 199024661722232586240, 27266378655945864314880, 2508506836347019516968960, 431463175851687356918661120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS psi(n) is the sum of the totatives of n (A023896). LINKS FORMULA a(n) = Product_{i=1..n} A057661(i). MATHEMATICA FoldList[Times[#1, #2] &, Array[Sum[Total@ Select[Range@ d, CoprimeQ[#, d] &], {d, Divisors@ #}] &, 19]] (* Michael De Vlieger, Dec 27 2016 *) PROG (MAGMA) [&*[&+[&+[h: h in [1..d] | GCD(h, d) eq 1]: d in Divisors(k)]: k in [1..n]]: n in [1..1000]] CROSSREFS Cf. A000010, A057661, A232533 (partial sums of A057661), A280132 (partial products of A029940). Sequence in context: A185135 A238805 A005867 * A192411 A179563 A079802 Adjacent sequences:  A280130 A280131 A280132 * A280134 A280135 A280136 KEYWORD nonn AUTHOR Jaroslav Krizek, Dec 27 2016 STATUS approved

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Last modified May 25 20:58 EDT 2020. Contains 334597 sequences. (Running on oeis4.)