A340370 a(n) = 1 if the odd part of n is a squarefree semiprime, 0 otherwise.

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

Offset

1

Links

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

Index entries for characteristic functions

Formula

a(n) = A280710(A000265(n)).

Prog

(PARI)
A000265(n) = (n>>valuation(n, 2));
A280710(n) = (bigomega(n)==2*issquarefree(n)); \\ After code in A280710.
A340370(n) = A280710(A000265(n));

Crossrefs

Characteristic function of A340380.

Cf. A000265, A280710.

Cf. also A340371.

Sequence in context: A353481 A353677 A353676 * A216038 A011728 A297043

Adjacent sequences: A340367 A340368 A340369 * A340371 A340372 A340373

Keyword

nonn

Author

Antti Karttunen, Jan 06 2021

Status

approved