A224718 Primes p such that p^2 + 1 is not squarefree.

7, 41, 43, 107, 157, 193, 239, 251, 257, 293, 307, 443, 457, 557, 577, 593, 607, 643, 743, 757, 829, 857, 907, 1093, 1193, 1303, 1307, 1451, 1483, 1493, 1543, 1607, 1657, 1693, 1723, 1789, 1907, 1993, 2143, 2207, 2243, 2267, 2293, 2309, 2357, 2393, 2543

Offset

1,1

Links

Zak Seidov, Table of n, a(n) for n = 1..1000

Example

7^2 + 1 = 50 = 2*5^2, 41^2 + 1 = 1681 = 2*29^2.

Mathematica

Select[Prime[Range[300]], ! SquareFreeQ[#^2 + 1] &]

Crossrefs

Cf. A039787.

Sequence in context: A023251 A073501 A080666 * A272387 A338771 A161505

Adjacent sequences: A224715 A224716 A224717 * A224719 A224720 A224721

Keyword

nonn

Author

Zak Seidov, Apr 16 2013

Status

approved