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%I #2 Mar 30 2012 18:57:11
%S 2,3,4,5,9,8,7,25,27,6,11,49,125,10,32,13,121,343,14,243,64,17,169,
%T 1331,15,3125,729,12,19,289,2197,16,16807,15625,18,256,23,361,4913,21,
%U 161051,117649,20,6561,512,29,529,6859,22
%N Array: row n consists of the positive integers x for which there are exactly n positive integers y such that x+y divides x*y.
%C Many properties of the array follow easily from Comments at A063647:
%C 1. Every positive integer except 1 occurs, exactly once.
%C 2. Row 1 consists of the primes.
%C 3. Row k includes p^k for all primes p, for k>=1.
%C 4. Row 4 includes all products of two distinct primes.
%C 5. Column 1 consists of even numbers.
%e Corner of the array:
%e 2....3....5....7....11....13....
%e 4....9....25...49...121...169...
%e 8....27...125..343..1331..2197..
%e 6....10...14...15...16....21....
%e 6 is in row 4 because there are 4 numbers y for which
%e 6+y divides 6*y; they are 3,6,12,30.
%Y Cf. A063647.
%K nonn,tabl
%O 1,1
%A _Clark Kimberling_, Mar 12 2010
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