

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



KEYWORD

nonn


AUTHOR



STATUS

approved



