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A153639 Evilness of triangular numbers. 0
1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The evilness of a number is 1 if the number is evil and 0 otherwise. The number is evil if it has an even number of ones in its binary expansion.

LINKS

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

MATHEMATICA

od[n_] := Mod[Count[IntegerDigits[n, 2], 1], 2] Table[1 - od[n (n + 1)/2], {n, 0, 128}]

CROSSREFS

A000217 Triangular numbers. A001969 Evil numbers.

Sequence in context: A105594 A091949 A039984 * A103582 A129565 A121967

Adjacent sequences:  A153636 A153637 A153638 * A153640 A153641 A153642

KEYWORD

nonn

AUTHOR

Tanya Khovanova, Dec 29 2008

STATUS

approved

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Last modified August 17 22:32 EDT 2018. Contains 313817 sequences. (Running on oeis4.)