A373254 a(n) = 1 if A003415(n) == +1 (mod 3), otherwise 0, where A003415 is the arithmetic derivative.

0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1

Offset

0

Links

Antti Karttunen, Table of n, a(n) for n = 0..100000

Index entries for characteristic functions

Formula

a(n) = [A003415(n) == +1 (mod 3)], where [ ] is the Iverson bracket.

Prog

(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A373254(n) = (1==(A003415(n)%3));

Crossrefs

Characteristic function of A373255.

Cf. A003415, A373253.

Sequence in context: A095190 A131735 A131736 * A152228 A368625 A086823

Adjacent sequences: A373251 A373252 A373253 * A373255 A373256 A373257

Keyword

nonn

Author

Antti Karttunen, May 31 2024

Status

approved