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Parity of the multiplicative partition function A001055.
10

%I #23 Aug 08 2020 03:58:42

%S 1,1,1,0,1,0,1,1,0,0,1,0,1,0,0,1,1,0,1,0,0,0,1,1,0,0,1,0,1,1,1,1,0,0,

%T 0,1,1,0,0,1,1,1,1,0,0,0,1,0,0,0,0,0,1,1,0,1,0,0,1,1,1,0,0,1,0,1,1,0,

%U 0,1,1,0,1,0,0,0,0,1,1,0,1,0,1,1,0,0,0,1,1,1,0,0,0,0,0,1,1,0,0,1,1,1,1,1,1,0,1,0,1,1,0,0,1,1,0,0,0,0,0

%N Parity of the multiplicative partition function A001055.

%C Suggested by the title of a talk by Paul Pollack in the program for the 2011 Illinois Number Theory Conference.

%H T. D. Noe, <a href="/A190938/b190938.txt">Table of n, a(n) for n = 1..1000</a>

%H Paul Pollack, <a href="http://pollack.uga.edu/multpart.pdf">The parity of the multiplicative partition function</a>, Talk at 2011 Illinois number theory meeting.

%H Paul Pollack, <a href="http://dx.doi.org/10.1090/S0002-9939-2012-11254-7">On the parity of the number of multiplicative partitions and related problems</a>, Proc. Amer. Math. Soc. 140 (2012), 3793-3803.

%H A. Zaharescu and M. Zaki, <a href="https://www.semanticscholar.org/paper/On-the-parity-of-the-number-of-multiplicative-Zaharescu-Zaki/2f73099c652a7b1ed615772d6434249ddece3962">On the parity of the number of multiplicative partitions</a>, Acta Arith. 145 (2010), no. 3, 221-232. MR2733086. doi: 10.4064/aa145-3-2.

%F a(n) = A001055(n) mod 2.

%o (PARI) fcnt(n,m) = {local(s);s=0;if(n == 1,s=1,fordiv(n,d,if(d > 1 & d <= m,s=s+fcnt(n/d,d))));s}

%o vector(100, n, fcnt(n,n) % 2) \\ after _Michael B. Porter_ in A001055, _Michel Marcus_, Jun 21 2015

%Y Cf. A001055, A040051.

%K nonn

%O 1

%A _N. J. A. Sloane_, May 24 2011