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%I #9 Jun 16 2018 16:06:42
%S 4,6,20,30,60,270,630,728,1170,1638,1890,2310,2730,2970,4590,8190,
%T 8910,12870,14850,16830,17850,18018,18810,19110,19890,22230,27846,
%U 27930,33930,52290,56070,60512,61110,63630,64890,67410,68670,80730,86130
%N Composite numbers k such that the difference between the odd and even aliquot parts of k divides k.
%H Harry J. Smith, <a href="/A066193/b066193.txt">Table of n, a(n) for n = 1..290</a>
%t Do[ d = Drop[ Divisors[ n ], -1 ]; l = Length[ d ]; ev = 0; od = 1; k = 2; While[ k <= l, If[ EvenQ[ d[ [ k ] ] ], ev = ev + d[ [ k ] ], od = od + d[ [ k ] ] ]; k++ ]; If[ !PrimeQ[ n ] && IntegerQ[ n/ Abs[ ev - od ] ], Print[ n ] ], {n, 2, 10^5} ]
%o (PARI) { n=0; for (m=4, 10^9, if (isprime(m), next); d=divisors(m); s=1; for (i=2, numdiv(m) - 1, if (d[i]%2, s += d[i], s -= d[i])); if (s != 0 && m%s == 0, write("b066193.txt", n++, " ", m); if (n==1000, return)) ) } \\ _Harry J. Smith_, Feb 05 2010
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Dec 15 2001