cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A128446 Quotients A122000(p-1) / (2^p - 1), where p = prime(n) for n > 1.

Original entry on oeis.org

1, 882850585445281, 28084773172609134470952326813135521948919663474715912134590894817085103016117634792155856629828598766188378241
Offset: 2

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Author

Alexander Adamchuk, Mar 03 2007

Keywords

Comments

A014566(n) = n^n + 1 is a Sierpinski Number of the First Kind.
A014566(2^n - 1) is divisible by 2^n.
A122000(n) = ((2^n - 1)^(2^n - 1) + 1) / 2^n = A014566(2^n - 1) / 2^n = A081216(2^n - 1).
a(5) = 6.044...*10^3072, and is too large to include. - Amiram Eldar, Jul 17 2025

Crossrefs

Programs

  • Mathematica
    a[n_] := Module[{p = Prime[n]}, ((2^(p-1) - 1)^(2^(p-1) - 1) + 1)/(2^(p-1)*(2^p-1))]; Array[a, 3, 2] (* Amiram Eldar, Jul 17 2025 *)

Formula

a(n) = ((2^(prime(n)-1) - 1)^(2^(prime(n)-1)-1) + 1)/(2^(prime(n)-1)*(2^prime(n)-1)).