%I A042987
%S A042987 2,3,5,7,11,13,19,23,29,31,37,43,47,53,59,61,67,71,79,83,101,103,107,109,
%T A042987 127,131,139,149,151,157,163,167,173,179,181,191,197,199,211,223,227,229,
%U A042987 239,251,263,269,271,277,283,293,307,311,317,331,347,349,359,367,373,379
%N A042987 Primes congruent to {2, 3, 5, 7} mod 8.
%C A042987 Equivalently, primes p not congruent to 1 mod 8.
%C A042987 Achava Nakhash wrote: "In 1981 D. Weisser proved that a prime not congruent 
               to 1 mod 8 and >= 7 is irregular if and only if the rational number 
               Zeta_K(-1) is p-adically integral, that is has a denominator not 
               divisible by p, where K is the maximal real subfield of the cyclotomic 
               field of p'th roots of unity. His proof was very indirect, depending 
               upon a formula for the arithmetic genus of the Hilbert Modular Variety 
               of this field. - Vincenzo Librandi (vincenzo.librandi(AT)tin.it), 
               Feb 21 2009
%H A042987 Achava Nakhash, <a href="http://mathforum.org/kb/thread.jspa?forumID=253&threadID=1872454">
               Irregular Primes and Dedekind Zeta Functions</a> [From Vincenzo Librandi 
               (vincenzo.librandi(AT)tin.it), Feb 21 2009]
%Y A042987 Complement in primes of A007519.
%Y A042987 Sequence in context: A105049 A057447 A095074 this_sequence A097375 A007459 
               A129944
%Y A042987 Adjacent sequences: A042984 A042985 A042986 this_sequence A042988 A042989 
               A042990
%K A042987 nonn
%O A042987 1,1
%A A042987 N. J. A. Sloane (njas(AT)research.att.com).
%E A042987 More terms from Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 
               21 2009