A373264 a(n) = 1 if n' / gcd(n,n') is of the form 4m+2, otherwise 0, where n' stands for the arithmetic derivative of n, A003415.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

Formula

a(n) = [A083345(n) == 2 (mod 4)], where [ ] is the Iverson bracket.

a(n) = A369001(n) - A369004(n).

Prog

(PARI)
A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
A373264(n) = (2==(A083345(n)%4));

Crossrefs

Characteristic function of A373265.

Cf. A003415, A083345, A369001, A369004.

Sequence in context: A366289 A037824 A025461 * A169674 A324053 A353480

Adjacent sequences: A373261 A373262 A373263 * A373265 A373266 A373267

Keyword

nonn,easy

Author

Antti Karttunen, Jun 01 2024

Status

approved