A154887 Number of ways to partition n into distinct reduced fractions i/j with j <= n.

1, 2, 11, 71, 838, 7915, 181443, 3529287, 130501170, 4118232210, 269279551654, 9556917233108, 1003141976524301, 74252913818290142, 14979717449141067931, 1451159432555957095630, 363482056748832080145666, 28348494499719127795555178, 10422254792015005991605309232

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Example

a(3) = #{3, 8/3+1/3, 5/2+1/2, 7/3+2/3, 2+1, 2+2/3+1/3, 5/3+4/3, 5/3+1+1/3, 3/2+1+1/2, 3/2+2/3+1/2+1/3, 4/3+1+2/3} = 11. - corrected by Reinhard Zumkeller, Feb 02 2009

Crossrefs

Cf. A143270, A154886, A154888.

Sequence in context: A214692 A186633 A291301 * A371518 A363389 A323842

Adjacent sequences: A154884 A154885 A154886 * A154888 A154889 A154890

Keyword

nonn

Author

Reinhard Zumkeller, Jan 17 2009

Extensions

More terms from Jinyuan Wang, Dec 13 2024

Status

approved