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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

Table of n, a(n) for n=0..104.

MATHEMATICA

w[n_] := IntegerDigits[n, 2] // Total;

a[n_] := If[n == 1, -1, 2 Boole[w[n] == 2]];

a /@ Range[0, 104] (* Jean-Fran├žois 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.)