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 A151758 G.f.: Theta^2-Theta, where Theta = Sum_{k>=0} x^(2^k). 5
 0, -1, 0, 2, 0, 2, 2, 0, 0, 2, 2, 0, 2, 0, 0, 0, 0, 2, 2, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS If we omit the "-x" term and divide by 2, we get the characteristic function of the numbers with binary weight 2 (A018900, A151774). LINKS MATHEMATICA w[n_] := IntegerDigits[n, 2] // Total; a[n_] := If[n == 1, -1, 2 Boole[w[n] == 2]]; a /@ Range[0, 104] (* Jean-François Alcover, Mar 31 2021 *) CROSSREFS Cf. A000079, A073267, A151759, A151760, A151761, A151762, A018900, A151774. Sequence in context: A343723 A260149 A091379 * A164272 A164273 A307694 Adjacent sequences:  A151755 A151756 A151757 * A151759 A151760 A151761 KEYWORD sign AUTHOR N. J. A. Sloane, Jun 22 2009 STATUS approved

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Last modified June 19 12:55 EDT 2021. Contains 345129 sequences. (Running on oeis4.)