A120796 Denominators of partial sums of Catalan numbers scaled by powers of -1/20.

1, 20, 200, 1600, 80000, 1600000, 16000000, 1280000000, 512000000, 256000000000, 2560000000000, 102400000000000, 1024000000000000, 4096000000000000, 40960000000000000, 6553600000000000000

Offset

0,2

Comments

Numerators are given under A120791.

Links

Table of n, a(n) for n=0..15.

Formula

a(n)=denominator(r(n)), with the rationals r(n):=sum(((-1)^k)*C(k)/20^k,k=0..n) with C(k):=A000108(k) (Catalan numbers). Rationals r(n) are taken in lowest terms.

Crossrefs

Sequence in context: A045758 A035474 A103261 * A120787 A223753 A099197

Adjacent sequences: A120793 A120794 A120795 * A120797 A120798 A120799

Keyword

nonn,easy,frac

Author

Wolfdieter Lang, Jul 20 2006

Status

approved