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Primes congruent to +/-1 or +/-7 modulo 25.
1

%I #4 Oct 04 2021 17:00:26

%S 7,43,101,107,149,151,157,193,199,251,257,293,307,349,401,443,449,457,

%T 499,557,593,599,601,607,643,701,743,751,757,857,907,1049,1051,1093,

%U 1151,1193,1201,1249,1301,1307,1399,1451,1493,1499,1543,1549,1601,1607

%N Primes congruent to +/-1 or +/-7 modulo 25.

%C Equivalently, primes p such that the smallest extension of F_p containing the 5th roots of unity also contains the 25th roots of unity.

%C In this respect, the sequence is the n=5 instance of a family of sequences. For n=3, see A129805, and for n=2, see A002144.

%C Equivalently, the primes p for which, if p^t = 1 mod 5, then p^t = 1 mod 25.

%F A141927 U A141932 U A141946 U A141941. [From _R. J. Mathar_, Feb 05 2010]

%K easy,nonn

%O 1,1

%A _Katherine E. Stange_, Feb 03 2010

%E More terms from _R. J. Mathar_, Feb 05 2010