This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A070179 Primes p such that x^2 = 2 has a solution mod p, but x^(2^2) = 2 has no solution mod p. 17
 17, 41, 97, 137, 193, 241, 313, 401, 409, 433, 449, 457, 521, 569, 641, 673, 761, 769, 809, 857, 929, 953, 977, 1009, 1129, 1297, 1321, 1361, 1409, 1489, 1657, 1697, 1873, 1993, 2017, 2081, 2137, 2153, 2161, 2297, 2377, 2417, 2521, 2609, 2617, 2633, 2713 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Complement of A014754 with regard to primes of the form 8*k+1. These appear to be the primes p for which 4^((p-1)*n/8) mod p = (p-2)*( n mod 2)+1. For example, 4^(5*n) mod 41 = 1,40,1,40,1,40...= 39*(n mod 2)+1 and 4^(30*n) mod 241 = 1,240,1,240,1,240...= 239*(n mod 2) +1. - Gary Detlefs, Jul 06 2014 Primes p == 1 mod 8 such that 2^((p-1)/4) == -1 mod p. - Robert Israel, Jul 06 2014 A very similar sequence is A293394. - Jonas Kaiser, Nov 08 2017 LINKS Bruno Berselli, Table of n, a(n) for n = 1..1000 FORMULA Primes of the form 8*k + 1 but not x^2 + 64*y^2. - Michael Somos, Mar 22 2008 a(n) ~ 8n log n. - Charles R Greathouse IV, Nov 10 2017 MAPLE select(p -> isprime(p) and 2 &^((p-1)/4) mod p = p-1, [8*k+1\$k=1..10000]); # Robert Israel, Jul 06 2014 PROG (PARI) forprime(p=2, 2720, x=0; while(x

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