A103308 Reduced denominators of the central moments of the distribution of random line segments picked on a unit line segment.

18, 135, 135, 1701, 20412, 1458, 32805, 1082565, 144342, 2302911, 48361131, 18600435, 191318760, 975725676, 243931419, 2453663097, 14721978582, 903981141, 268482398877, 2646469360359, 962352494676, 4707158941350

Offset

2,1

Links

Table of n, a(n) for n=2..23.

Eric Weisstein's World of Mathematics, Line Line Picking.

Formula

a(n) = denominator((2^(n+3)+(-1)^n*2*(3*n+5))/((n+1)*(n+2)*3^(n+2))). - Amiram Eldar, Apr 14 2022

Example

1/18, 1/135, 1/135, 4/1701, 31/20412, 1/1458, 13/32805, 224/1082565, ...

Mathematica

a[n_] := Denominator[(2^(n + 3) + (-1)^n*2*(3*n + 5))/((n + 1)*(n + 2)*3^(n + 2))]; Array[a, 20, 2] (* Amiram Eldar, Apr 14 2022 *)

Crossrefs

Cf. A103307 (numerators).

Sequence in context: A299932 A058649 A273222 * A320677 A010824 A022710

Adjacent sequences: A103305 A103306 A103307 * A103309 A103310 A103311

Keyword

nonn,frac

Author

Eric W. Weisstein, Jan 28 2005

Status

approved