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 A280458 Partial products of A023896. 0
 1, 1, 3, 12, 120, 720, 15120, 241920, 6531840, 130636800, 7185024000, 172440576000, 13450364928000, 564915326976000, 33894919618560000, 2169274855587840000, 295021380359946240000, 15931154539437096960000, 2724227426243743580160000, 217938194099499486412800000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A023896(n) = the sum of totatives of n. a(n) = n! for n = 1, 5 and 6. LINKS FORMULA a(n) = Sum_{i=1..n} A023896(i). MATHEMATICA FoldList[#1 #2 &, Table[Ceiling[(n EulerPhi@ n)/2], {n, 20}]] (* Michael De Vlieger, Jan 03 2017 *) PROG (MAGMA) [&*[&+[h: h in [1..k] | GCD(h, k) eq 1]: k in [1..n]]: n in [1..100]] CROSSREFS Cf. A023896, A213544 (partial sums of A023896). Sequence in context: A009254 A133987 A194506 * A294198 A133553 A010571 Adjacent sequences:  A280455 A280456 A280457 * A280459 A280460 A280461 KEYWORD nonn AUTHOR Jaroslav Krizek, Jan 03 2017 STATUS approved

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Last modified July 24 14:51 EDT 2021. Contains 346273 sequences. (Running on oeis4.)