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%I #9 Aug 16 2013 23:35:22
%S 1,1,1,1,2,2,4,3,4,3,5,3,7,5,6,5,9,5,10,5,7,7,11,5,10,8,9,7,14,6,14,8,
%T 11,10,12,7,17,11,12,8,18,8,18,10,11,12,19,8,18,12,16,12,22,10,17,11,
%U 17,16,25,9,25,17,16,14,22,13,28,16,22,15,31,12,32,21,20,18,27,16,34,15,24
%N Least positive integer k such that k*sigma(n) forms an increasing sequence.
%H Paul D. Hanna, <a href="/A224901/b224901.txt">Table of n, a(n) for n = 1..10000</a>
%e The product a(n)*sigma(n) forms an increasing sequence that begins:
%e [1, 3, 4, 7, 12, 24, 32, 45, 52, 54, 60, 84, 98, 120, 144, 155, 162, 195, ...].
%o (PARI) a(n)=if(n==1,1,(a(n-1)*sigma(n-1))\sigma(n)+1)
%o for(n=1,80,print1(a(n),", "))
%K nonn
%O 1,5
%A _Paul D. Hanna_, Aug 16 2013
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