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A217858 Odd part of lcm(1,2,3,...,n). 3
1, 1, 3, 3, 15, 15, 105, 105, 315, 315, 3465, 3465, 45045, 45045, 45045, 45045, 765765, 765765, 14549535, 14549535, 14549535, 14549535, 334639305, 334639305, 1673196525, 1673196525, 5019589575, 5019589575, 145568097675, 145568097675, 4512611027925, 4512611027925, 4512611027925 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..33.

FORMULA

a(n) = A000265( A003418(n) ).

a(n) = lcm_{1 <= k <= n, k odd}. - Peter Luschny, Oct 15 2012

EXAMPLE

a(8) is the least common multiple of {1,3,5,7}.

MAPLE

A217858 := n -> ilcm(op(select(j->j mod 2 = 1, [$1..n]))):

seq(A217858(i), i = 1..33); # Peter Luschny, Oct 15 2012

MATHEMATICA

a[n_] := LCM @@ Select[Range[n], OddQ]; Array[a, 33] (* Jean-Fran├žois Alcover, Jun 27 2019 *)

PROG

(PARI)

A003418(n) = lcm(vector(n, k, k));

A000265(n) = n/2^valuation(n, 2);

a(n) = A000265( A003418(n) );

(Sage)

def A217858(n): return lcm([j for j in (1..n) if is_odd(j)])

[A217858(n) for n in (1..33)]  # Peter Luschny, Oct 15 2012

CROSSREFS

Cf. A003418, A128501, A216917.

Sequence in context: A100735 A129356 A290344 * A185275 A055634 A133221

Adjacent sequences:  A217855 A217856 A217857 * A217859 A217860 A217861

KEYWORD

nonn

AUTHOR

Joerg Arndt, Oct 13 2012

STATUS

approved

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Last modified May 9 05:09 EDT 2021. Contains 343688 sequences. (Running on oeis4.)