A131446 Denominators of n-th approximation of factorial (also called harmonic) expansion of Pi.

1, 1, 1, 8, 15, 720, 5040, 13440, 13440, 3628800, 532224, 43545600, 691891200, 691891200, 108972864000, 1902071808000, 118562476032000, 6847458508800, 24329020081766400, 17888985354240000, 1344498478202880000

Offset: 1

Author

Wolfdieter Lang, Aug 07 2007

Keywords

• nonn
• frac
• easy

Comments

Numerators are given in A131445.

For the rationals r(n) and some values see the W. Lang link under A131445.

Examples

			Rationals r(n): [3,3,3,25/8,47/15,2261/720,15833/5040,42223/13440,42223/13440,...].
		

Crossrefs

Cf. A000796, A131445.

Formula

a(n) = denominator(r(n)), with r(n):=sum(b(k)/k!,n=1..n) with b(k):=A075874(k) (factorial expansion of Pi).