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.

A225856 Primes p such that p^2 + 1 is squarefree.

Original entry on oeis.org

2, 3, 5, 11, 13, 17, 19, 23, 29, 31, 37, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 109, 113, 127, 131, 137, 139, 149, 151, 163, 167, 173, 179, 181, 191, 197, 199, 211, 223, 227, 229, 233, 241, 263, 269, 271, 277, 281, 283, 311, 313, 317, 331, 337
Offset: 1

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Author

Rafael Parra Machio, May 18 2013

Keywords

Comments

Primes of the sequence A224718 generating squarefree.

Examples

			23 is a term since 23^2+1 = 530 = 2*5*53, is squarefree.
43 is not a term since 43^2+1 = 1850 = 2*5^2*7, is not squarefree.
		

Crossrefs

Intersection of A000040 and A049533.
Cf. A224718.

Programs

  • Mathematica
    Select[Prime[Range[100]], SquareFreeQ[#^2+1]&]