%I #6 Sep 24 2013 20:51:06
%S 2,-1,-4,-40,-4960,-147166720,-299211527038566400,
%T -2703337074029927682081937523621232640
%N The number 2 (that is, 1+1) in the Witt vector ring for p=2 over the integers.
%D Jean-Pierre Serre, Local Fields (Corps Locaux), chapter 2, paragraph 6
%F Sum(2^j*a(j)^(2^(i-j)), j=0..i)=2 for all i.
%e a(0)^4 + 2*a(1)^2 + 4*a(2) = 2^4 + 2*(-1)^2 + 4*(-4) = 16+2-16 = 2.
%Y Cf. A006173 and others.
%K sign
%O 0,1
%A _David A. Madore_, Jun 15 2001