The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A225856 Primes p such that p^2 + 1 is squarefree. 2
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes of the sequence A224718 generating squarefree. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 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. MATHEMATICA Select[Prime[Range[100]], SquareFreeQ[#^2+1]&] CROSSREFS Intersection of A000040 and A049533. Cf. A224718. Sequence in context: A187921 A275059 A072538 * A322173 A216509 A075237 Adjacent sequences:  A225853 A225854 A225855 * A225857 A225858 A225859 KEYWORD nonn AUTHOR Rafael Parra Machio, May 18 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 14 09:06 EDT 2021. Contains 345018 sequences. (Running on oeis4.)