A368994 a(n) = 1 if A342001(k) is a multiple of four, and 0 otherwise.

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

Offset

1

Comments

Asymptotic mean of this sequence seems to be about 0.208..., i.e., about half what it is for A368997.

Links

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

Index entries for characteristic functions

Formula

a(n) = A121262(A342001(n)).

a(n) <= A353494(n).

a(n) <= A368997(n) <= A358680(n).

Prog

(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A003557(n) = (n/factorback(factorint(n)[, 1]));
A342001(n) = (A003415(n) / A003557(n));
A368994(n) = !(A342001(n)%4);

Crossrefs

Cf. A003415, A121262, A342001, A353494, A358680, A368997.

Characteristic function of A368995.

Sequence in context: A100910 A369004 A359605 * A217096 A014036 A014063

Adjacent sequences: A368991 A368992 A368993 * A368995 A368996 A368997

Keyword

nonn

Author

Antti Karttunen, Jan 14 2024

Status

approved