

A064889


Denominators of partial sums of reciprocals of A051451 (A051451 includes lcm(1,...,x), x=power of prime from A000961 and also contains 1).


0



1, 2, 3, 4, 30, 420, 840, 1260, 9240, 9009, 240240, 471240, 232792560, 535422888, 26771144400, 181704600, 4822131600, 36100888223400, 3702655202400, 76327592243760, 737576396429600, 362291852261631600, 6416241209619040800
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..23.


FORMULA

a(n) = denominator(Sum_{k=1..n} 1/A051451(k)).


EXAMPLE

n=6, sum = (1/1) + (1/2) + (1/6) + (1/12) + (1/60) + (1/420) = 743/420, the denominator = a(6) = 743. Remark: If 1 is omitted from A051451, the denominators of partial sums of reciprocals do not change; however, numerators are changing, not compatible with these denominators (see A064888).


CROSSREFS

Cf. A051451, A003418, A000961, A064857, A064858, A064859, A064888, A064890.
Sequence in context: A007114 A191471 A305205 * A057917 A250189 A255253
Adjacent sequences: A064886 A064887 A064888 * A064890 A064891 A064892


KEYWORD

frac,nonn


AUTHOR

Labos Elemer, Oct 11 2001


STATUS

approved



