Search: id:A086823 Results 1-1 of 1 results found. %I A086823 %S A086823 0,0,1,1,1,1,1,0,0,1,1,1,1,1,0,0,1,0,1,1,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0, %T A086823 0,1,1,0,0,1,0,1,1,0,1,1,0,0,0,0,1,1,0,0,0,0,1,1,1,1,1,0,0,0,0,1,1,0,0, %U A086823 1,0,1,1,0,1,0,0,1,0,0,1,1,1,0,1,0,0,1,0,0,1,0,1,0,0,1,0,0,0,1,0,1,0,1 %V A086823 0,0,1,1,1,1,1,0,0,1,1,-1,1,1,0,0,1,0,1,-1,0,1,1,0,0,1,0,-1,1,0,1,0,0, 1,0,0,1,1,0,0,1, %W A086823 0,1,-1,0,1,1,0,0,0,0,-1,1,0,0,0,0,1,1,1,1,1,0,0,0,0,1,-1,0,0,1,0,1,1, 0,-1,0,0,1,0,0,1, %X A086823 1,1,0,1,0,0,1,0,0,-1,0,1,0,0,1,0,0,0,1,0,1,0,1 %N A086823 Coefficient of x^2 in the n-th cyclotomic polynomial. (The same as the coefficient of x^(phi(n)-2) ). %F A086823 if n is odd a(n) = 1/2 * mu(n)*(mu(n)-1) if n is even a(n) = 1/2 * mu(n)*(mu(n)-1) - mu(n/2). %o A086823 (PARI) a(n) = polcoeff(polcyclo(n), 2); (Wasserman) %Y A086823 Cf. A008683, A000010. %Y A086823 Sequence in context: A131735 A131736 A152228 this_sequence A104121 A157928 A159075 %Y A086823 Adjacent sequences: A086820 A086821 A086822 this_sequence A086824 A086825 A086826 %K A086823 sign %O A086823 3,1 %A A086823 Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 07 2003 %E A086823 More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Mar 29 2005 Search completed in 0.001 seconds