A072165 Values of Moebius function of the products of two (not necessarily distinct) primes (semiprimes or 2-almost primes, A001358).

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

Offset

1,1

Comments

Characteristic function for numbers n such that A001358(n) is not a square. - Antti Karttunen, Oct 04 2017

Links

Antti Karttunen, Table of n, a(n) for n = 1..3001

Kimberly Schneider, Moebius function.

Index entries for characteristic functions

Formula

a(n) = A008683(A001358(n)). - Antti Karttunen, Oct 04 2017

Example

For n = 2995, A001358(2995) = 11449 = 107^2, and as Moebius mu is zero for squares, we have a(2995) = 0. - Antti Karttunen, Oct 04 2017

Maple

semiprimes := proc(d_n) local a, i; a := [ ]; for i from 1 to d_n do if((tau(i) = 3) or ((mobius(i) <> 0) and (tau(i) = 4))) then a := [ op(a), mobius(i) ]; fi; od: RETURN(a); end;

Crossrefs

Cf. A001358, A008683.

Sequence in context: A288864 A115971 A320007 * A358224 A072608 A295304

Adjacent sequences: A072162 A072163 A072164 * A072166 A072167 A072168

Keyword

easy,nonn

Author

Jani Melik, Jun 28 2002

Extensions

More terms from Antti Karttunen, Oct 04 2017

Status

approved