A103308 - OEIS

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

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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