Search: id:A053866 Results 1-1 of 1 results found. %I A053866 %S A053866 0,1,1,0,1,0,0,0,1,1,0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0, %T A053866 0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0, %U A053866 0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0 %N A053866 Parity of sum of divisors of n. %H A053866 Michael Gilleland, Some Self-Similar Integer Sequences %F A053866 a(n) = A000203(n) mod 2. a(n)=1 iff n>0 is a square or twice a square. %F A053866 Multiplicative with a(2^e)=1, a(p^e)=1 if e even, 0 otherwise. %F A053866 Dirichlet g.f.: zeta(2s)(1+2^-s). - Michael Somos Apr 12 2004 %o A053866 (PARI) a(n)=if(n<1,0,issquare(n)|issquare(2*n)) /* Michael Somos Apr 12 2004 */ %Y A053866 Cf. A000203, A028982. %Y A053866 A093709(n)=a(n) if n>0. %Y A053866 Sequence in context: A079336 A057215 A029691 this_sequence A156595 A143222 A010060 %Y A053866 Adjacent sequences: A053863 A053864 A053865 this_sequence A053867 A053868 A053869 %K A053866 nonn,mult %O A053866 0,1 %A A053866 Henry Bottomley (se16(AT)btinternet.com), Mar 29 2000 %E A053866 More terms from James A. Sellers (sellersj(AT)math.psu.edu), Apr 08 2000 Search completed in 0.001 seconds