[seqfan] Re: A093893 Subsequence

Max Alekseyev maxale at gmail.com
Sat May 30 21:48:06 CEST 2009


On Fri, May 29, 2009 at 6:14 PM, Hagen von EItzen <math at von-eitzen.de> wrote:

> //////a(12) <= 2311^11////////////
> a(13) = //////2311^12 = 23205949656945057666311162427422570380321,
> //////a(14) <= //////2311^13,
> //////a(15) <= 92401^14 ~ 3.3*10^69; if of the form////// p^4*q^2, then p>10^4 or q>10^4.
> //////a(16) = //////???, //////

Update:

exact value:
a(12) = 211^3 * 1471^2 = 20326973048971

upper bounds:
a(14) <= 2311^6 * 50821 = 7741816606631194948471381
a(15) <= 120121^4 * 150151^2 = 4693882500443399337067739425681
a(16) <= 120121 * 150151 * 180181 * 270271 = 878325738218239130821
a(18) <= 4084081^2 * 5105101^2 * 8168161 = 3550762793626881654061078595276521
a(19) <= 4084081^18

For exact value of a(14), if it is not 7741816606631194948471381, then
a(14) = p^6*q where prime p<1400 and prime q>10^6.

Max




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