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%I #11 Oct 29 2023 01:52:01
%S 8,9,12,16,18,20,24,25,27,28,32,36,40,44,45,48,49,50,52,54,56,60,63,
%T 64,68,72,75,76,80,81,84,88,90,92,96,98,99,100,104,108,112,116,117,
%U 120,121,124,125,126,128,132,135,136,140,144,147,148,150,152,153,156,160
%N Numbers k such that there are infinitely many multiples of k that have exactly k divisors.
%C Regional Math Competition for Northwestern Bulgaria, Vraca 2003, Problem 12/3.
%C Sequence consists of all nonsquarefree numbers except for the number 4.
%e 8 is a term because all numbers of the form 2^3*p (where p is an odd prime) have exactly 8 divisors and are multiples of 8.
%e Any squarefree number has only a finite number of such multiples. The number 4 has only one such multiple (8).
%Y Cf. A013929.
%K nonn
%O 1,1
%A _Ivaylo Kortezov_, Mar 09 2003
%E Edited by _Jon E. Schoenfield_, Oct 28 2023
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