A064889 Denominators of partial sums of reciprocals of A051451 (A051451 includes lcm(1,...,x), x=power of prime from A000961 and also contains 1).

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

Offset: 1

Author

Labos Elemer, Oct 11 2001

Keywords

• frac
• nonn

Examples

			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.

Formula

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