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.

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A053609 Primes of form x^2+1 where x = LCM(1,2,...,k) for some k.

Original entry on oeis.org

2, 5, 37, 176401, 129859329601, 516625648014869290354797521879383114125823989794742396526049715541246671360001
Offset: 1

Views

Author

Labos Elemer, Feb 09 2000

Keywords

Comments

The next term has k > 10^4, if it exists. - Amiram Eldar, Aug 23 2024

Crossrefs

Cf. A049536, A046029, A051739, A051418, A051451, A053608.

Programs

  • Mathematica
    Select[FoldList[LCM, 1, Select[Range[100], PrimePowerQ]]^2 + 1, PrimeQ] (* Amiram Eldar, Aug 23 2024 *)

Formula

a(n) = A053608(A053608(n)) = A053608(n)^2 + 1. - Amiram Eldar, Aug 23 2024
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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