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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
OFFSET
1,3
COMMENTS
A023896(n) = the sum of totatives of n.
a(n) = n! for n = 1, 5 and 6.
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: A133987 A359658 A194506 * A294198 A133553 A010571
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Jan 03 2017
STATUS
approved