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A072165
Values of Moebius function of the products of two (not necessarily distinct) primes (semiprimes or 2-almost primes, A001358).
1
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
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
Sequence in context: A288864 A115971 A320007 * A358224 A072608 A295304
KEYWORD
easy,nonn
AUTHOR
Jani Melik, Jun 28 2002
EXTENSIONS
More terms from Antti Karttunen, Oct 04 2017
STATUS
approved