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 2007-08-25, 12:14 #1 devarajkandadai     May 2004 31610 Posts A new sequence A 132469 (OEIS) is a new sequence. A.K.Devaraj
 2007-08-25, 15:23 #2 Jens K Andersen     Feb 2006 Denmark 2×5×23 Posts A132469(n) = (2^(5n)-1)/31 = (32^n-1)/31 = base 32 generalized repunits.
2020-12-01, 21:23   #3
sweety439

Nov 2016

53148 Posts

Quote:
 Originally Posted by Jens K Andersen A132469(n) = (2^(5n)-1)/31 = (32^n-1)/31 = base 32 generalized repunits.
There are no primes in this sequence, since 32^n-1 = (2^n-1) * (16^n+8^n+4^n+2^n+1), and since the two factors are both >31 for n>5 ((32^n-1)/31 is not prime for all 1<=n<=5), thus the factorization is not trivial.

 2020-12-01, 22:08 #4 VBCurtis     "Curtis" Feb 2005 Riverside, CA 10010000011012 Posts You're only 13 years late, and not even on-topic. https://en.wikipedia.org/wiki/Intern...m#Necroposting

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