

A195905


Primes of the form 10 * n^2 + 7.


2



7, 17, 47, 97, 167, 257, 367, 647, 1217, 1447, 1697, 2897, 3617, 4007, 5297, 6257, 7297, 9007, 10247, 12967, 13697, 14447, 15217, 16007, 26017, 28097, 29167, 32497, 33647, 36007, 37217, 38447, 42257
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OFFSET

1,1


COMMENTS

First seven numbers of the form 10 * n^2 + 7 are prime numbers. They are called Trotter primes by Terrel Trotter Jr. There are 735 Trotter primes less than 10^8.


LINKS

T. Trotter, Trotter numbers and Trotter primes [Warning: As of March 2018 this site appears to have been hacked. Proceed with great caution. The original content should be retrieved from the Wayback machine and added here.  N. J. A. Sloane, Mar 29 2018]


MATHEMATICA

Select[(10*Range[0, 70]^2+7), PrimeQ] (* Harvey P. Dale, Dec 11 2018 *)


PROG

(Magma) [a: n in [0..300]  IsPrime(a) where a is 10*n^2+7]; // Vincenzo Librandi, Dec 05 2011


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



EXTENSIONS



STATUS

approved



