[seqfan] Re: Insert "+" and always get a prime
M. F. Hasler
seqfan at hasler.fr
Sun Dec 28 16:55:07 CET 2014
Eric, Lars, SeqFans,
I have finally submitted this (including single digit terms) as
https://oeis.org/draft/A252495 :
"Restricted magnanimous numbers: numbers such that the sum obtained by
inserting a "+" anywhere between two digits gives a prime, but no
"leading zeros" may appear."
Actually, the idea of "leading zeros are forbidden in the sums" could
also lead to the variants where such sums are simply not considered
(which would rather add than remove terms w.r.t. magnanimous numbers
A252996).
Anticipating, best wishes for 2015,
Maximilian
On Mon, Dec 22, 2014 at 10:49 AM, Eric Angelini <Eric.Angelini at kntv.be> wrote:
> Hello SeqFans,
> Look at those integers:
>
> 110,112,116,118,130,136
>
> You will always get a prime if you insert
> a "+" sign inside them, no matter where:
>
> 110 --> 1+10=11 and 11+0=11
> 112 --> 1+12=13 and 11+2=13
> 116 --> 17
> 118 --> 19
> 130 --> 1+30=31 and 13+0=13
> 136 --> 1+36=37 and 13+6=19
>
> 101 is not an integer with this property
> as 1+01=2 is not allowed (no substring
> starting with "0").
>
> I guess S, the sequence of integers that
> share this property) will start like this:
>
> S = 11, 12, 14, 16, 20, 21, 23, 25, 29, 30, 32, 34, 38, 41, 43, 47, 49, 50, 52, 56, 58, 61, 65, 67, 70, 74, 76, 83, 85, 89, 92, 94, 98, 110, 112, 116, 118, 130, 136,...
> Best,
> É.
>
>
>
>
>
>
>
>
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
--
Maximilian
More information about the SeqFan
mailing list