mersenneforum.org What's the next term in the sequence (part deux)?
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 2007-01-11, 01:49 #1 grandpascorpion     Jan 2005 Transdniestr 503 Posts What's the next term in the sequence (part deux)? 5,22,102,510,82110,17490,? The solution involves basic number theory. 39 and values derived from fitted polynomials aren't what I'm looking for :) Last fiddled with by grandpascorpion on 2007-01-11 at 02:23 Reason: rounding errors gave bad values in the sequence
 2007-01-11, 03:39 #2 grandpascorpion     Jan 2005 Transdniestr 1111101112 Posts Ugh, one of the terms was wrong. Here's the correct sequence: 5,22,102,510,3210,17490,?
2007-01-11, 08:36   #3
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Quote:
 Originally Posted by grandpascorpion 5,22,102,510,82110,17490,? The solution involves basic number theory. 39 and values derived from fitted polynomials aren't what I'm looking for :)
42 ;-)

Paul

 2007-01-11, 09:52 #4 akruppa     "Nancy" Aug 2002 Alexandria 2,467 Posts %I A048251 %S A048251 5,22,102,510,3210,17490,112890,600270 %N A048251 Smallest number whose sum of divisors is 6^n. %F A048251 a(n)=Min{x : A000203(x)=6^n} %e A048251 Sigma[x]=1296=6.6.6.6 if x={510, 642, 710, 742, 782, 795, 862, 935, 1177, 1207, 1219}; the smallest is a(4)=510. %Y A048251 A006532, A020477, A019422, A019423, A018427. %Y A048251 Sequence in context: A083586 A087439 A033452 this_sequence A017971 A017972 A008485 %Y A048251 Adjacent sequences: A048248 A048249 A048250 this_sequence A048252 A048253 A048254 %K A048251 nonn %O A048251 1,1 %A A048251 Labos E. (labos(AT)ana.sote.hu) Alex
 2007-01-11, 13:19 #5 grandpascorpion     Jan 2005 Transdniestr 503 Posts Yep, I came up with this and found the sequence later (once the minimum terms were correct). I was thinking that the sigma would be the perfect power of a number n such that n had two or more factors. In this context, that would seem to mean n=2*3. That would be an interesting thing to prove I think. Last fiddled with by grandpascorpion on 2007-01-11 at 13:22

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