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 A228495 Characteristic function of the odd odious numbers (A092246). 5
 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS The following sequences all appear to have the same parity: A003071, A029886, A061297, A092524, A093431, A102393, A104258, A122248, A128975. - Jeremy Gardiner, Dec 28 2008. a(n+1) is the characteristic function of the even evil numbers (A125592). - Jeremy Gardiner, Feb 06 2015 LINKS Antti Karttunen, Table of n, a(n) for n = 0..65537 Tanya Khovanova, There are no coincidences, arXiv preprint 1410.2193 [math.CO], 2014. Index entries for characteristic functions. Index entries for sequences related to binary expansion of n. FORMULA a(2n) = 0, a(2n+1) = A092436(n). a(n) = A000035(n) * A010060(n). - Antti Karttunen, Jan 12 2019 MATHEMATICA a[n_] := If[OddQ[n] && OddQ[DigitCount[n, 2, 1]], 1, 0]; Array[a, 100, 0] (* Amiram Eldar, Aug 06 2023 *) PROG (PARI) a(n)=if(n%2==0, 0, subst(Pol(binary((n-1)/2)), x, 1)%2==0) (PARI) A228495(n) = ((n%2)&&(hammingweight(n)%2)); \\ Antti Karttunen, Jan 12 2019 (Python) def A228495(n): return n.bit_count()&1&n # Chai Wah Wu, Mar 03 2023 CROSSREFS Cf. A000035, A010060, A092246, A092436, A125592, A254379. Cf. A003071, A029886, A061297, A092524, A093431, A102393, A104258, A122248, A128975. Sequence in context: A300477 A355202 A353556 * A356982 A284683 A369968 Adjacent sequences: A228492 A228493 A228494 * A228496 A228497 A228498 KEYWORD nonn,base AUTHOR Ralf Stephan, Aug 23 2013 STATUS approved

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Last modified July 18 13:57 EDT 2024. Contains 374378 sequences. (Running on oeis4.)