

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



