Re: [math-fun] Re: Car Talk and prime numbers
From: "Michael Kleber" <michael.kleber@gmail.com>
I asked this list on Saturday about deletable primes. Thanks to everyone who replied. But no one answered my specific question about the largest known deletable prime, so I'm adding these two sequences to the OEIS. Maybe someone would like to extend them!
%S A125589 2,13,103,1013,10039 %N A125589 Smallest n-digit base-10 deletable prime.
100103, 1000193, 10000931
100001903 1000009321 10000019321 100000124963 1000000129693 10000000370219 Worth double-checking, of course. Phil () ASCII ribbon campaign () Hopeless ribbon campaign /\ against HTML mail /\ against gratuitous bloodshed [stolen with permission from Daniel B. Cristofani] __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
On 1/9/07, Phil Carmody <thefatphil@yahoo.co.uk> wrote:
%S A125589 2,13,103,1013,10039 %N A125589 Smallest n-digit base-10 deletable prime.
100103, 1000193, 10000931
100001903 1000009321 10000019321 100000124963 1000000129693 10000000370219
My program says 13, 103, 1013, 10039, 100103, 1000193, 10000931 100001903 1000003957 10000003957 100000013957 1000000030957 so I only agree with one of these additional terms. Can anyone check 1000003957 to see if it is indeed a deletable prime? It's smaller than the alternative, so if it's correctly deletable then I think it's the correct next term. I have its deletion path as (1000003957 100003957 10003957 1003957 100957 10957 1097 197 97 7) so I think it's good, and thus have a fair bit of confidence in my remaining terms. More terms coming after someone checks these for me ... --Joshua Zucker
Bad form to follow up my own message, I know, but here's what I currently have for this sequence: 2 13 103 1013 10039 100103 1000193 10000931 100001903 1000003957 10000003957 100000013957 1000000030957 10000000301957 100000000730957 1000000000730957 10000000003632979 100000000007309357 --Joshua Zucker
participants (2)
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Joshua Zucker -
Phil Carmody