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 A153638 Odiousness of triangular numbers. 0
 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS The odiousness of a number is equal to 1 if the number is odious, meaning that it has an odd number of ones in its binary expansion. Otherwise, it is zero. LINKS EXAMPLE a(2) is 0, because the second triangular number is 3, which in binary is 11 and has an even number of ones. MATHEMATICA od[n_] := Mod[Count[IntegerDigits[n, 2], 1], 2] Table[od[n (n + 1)/2], {n, 0, 128}] CROSSREFS A000217 Triangular numbers. Sequence in context: A030213 A132151 A103588 * A122415 A109017 A110161 Adjacent sequences:  A153635 A153636 A153637 * A153639 A153640 A153641 KEYWORD nonn AUTHOR Tanya Khovanova, Dec 29 2008 STATUS approved

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Last modified October 23 10:10 EDT 2018. Contains 316525 sequences. (Running on oeis4.)