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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

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

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.)