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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: A288596 A284745 A103588 * A122415 A241666 A324539
KEYWORD
nonn
AUTHOR
Tanya Khovanova, Dec 29 2008
STATUS
approved

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Last modified June 17 15:57 EDT 2024. Contains 373463 sequences. (Running on oeis4.)