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A072121 a(1) = 1; for n > 1, a(n) = smallest number > a(n-1) having at least n divisors.

%I A072121 #17 Jan 10 2024 04:59:12
%S A072121 1,2,4,6,12,18,24,30,36,48,60,72,120,144,168,180,240,252,336,360,420,
%T A072121 480,504,540,720,840,900,960,1008,1080,1260,1320,1440,1680,1800,1980,
%U A072121 2160,2520,2640,2880,3360,3600,3780,3960,4200,4320,4620,4680,5040,6300
%N A072121 a(1) = 1; for n > 1, a(n) = smallest number > a(n-1) having at least n divisors.
%H A072121 Robert Israel, <a href="/A072121/b072121.txt">Table of n, a(n) for n = 1..1000</a>
%p A072121 f:= proc(n,a) local k;
%p A072121 for k from a+1 do
%p A072121   if numtheory:-tau(k) >= n then return k fi
%p A072121 od
%p A072121 end proc:
%p A072121 R:= 1: x:= 1:
%p A072121 for n from 2 to 100 do x:= f(n,x); R:= R,x od:
%p A072121 R; # _Robert Israel_, Jan 09 2024
%Y A072121 Cf. A069654, A061799.
%K A072121 nonn
%O A072121 1,2
%A A072121 _Vladeta Jovovic_, Jun 19 2002