A208450 Denominator of A010786(n+1) / A010786(n).

1, 2, 3, 4, 5, 6, 21, 16, 9, 10, 55, 12, 39, 112, 315, 16, 170, 18, 513, 80, 105, 22, 8855, 96, 75, 416, 3159, 28, 203, 30, 9765, 640, 132, 816, 32725, 36, 333, 304, 140049, 40, 13325, 42, 13545, 39424, 495, 46, 2080925, 288, 5292, 1600, 11475, 52, 117130

Offset: 1

Author

Reinhard Zumkeller, Feb 26 2012

Keywords

• nonn
• frac

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A208449 (numerator).

Cf. A007955, A377484.

Programs

Haskell

import Data.Ratio ((%), denominator)
a208450 n = a208450_list !! (n-1)
a208450_list = map denominator $
   zipWith (%) (tail a010786_list) a010786_list

Mathematica

A208450[n_] := Times @@ (# - 1) / GCD[Times @@ #, Times @@ (# - 1)] & [Rest[Divisors[n + 1]]];
Array[A208450, 100] (* Paolo Xausa, Feb 20 2025 *)

Formula

a(n) = A010786(n) / A208448(n).

a(n) = A377484(n+1)/gcd(A007955(n+1), A377484(n+1)). - Ridouane Oudra, Feb 08 2025