[seqfan] Re: Rif: A light variation

[M. F. Hasler]

On Wed, Jan 20, 2016 at 9:41 AM, M. F. Hasler <seqfan at hasler.fr> wrote:

> It seems that 114 is the first integer not in this sequence.
>

Actually, the numbers which do not appear in the sequence are those listed
in oeis.org/A076150 : Start of 10 consecutive composite numbers.

Maximilian


>
> On Wed, Jan 20, 2016 at 9:16 AM, <john.mason at lispa.it> wrote:
>
>> Hi
>> with regard to "and is a permutation of the integers >0":
>> There will be, at some time in the integers > 0, a sequence of one hundred
>> composite numbers.
>> Some of these, in particular in the middle, will never give a resulting
>> prime when added to the last (single) digit of a(n-1). Therefore they will
>> not be in a(n).
>> Therefore a(n) is not a permutation of the integers > 0, and it would be
>> fun to find the first integer not present!
>> john
>>
>>
>>
>>
>> Da:     Eric Angelini <Eric.Angelini at kntv.be>
>> Per:    Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
>> Data:   20/01/2016 10:57
>> Oggetto:        [seqfan] A light variation
>> Inviato da:     "SeqFan" <seqfan-bounces at list.seqfan.eu>
>>
>>
>>
>> Hello SeqFans,
>> here is https://oeis.org/A055265 :
>>
>> > a(n) is the smallest positive integer not already in the sequence
>> > such that a(n)+a(n-1) is prime, starting with a(1)=1.
>>
>> I propose this variant:
>>
>> E> a(n) is the smallest positive integer not already in the sequence
>> E> such that a(n)+[the last digit of a(n-1)] is prime, starting with
>> a(1)=1.
>>
>> I guess E starts like this (and is a permutation of the integers >0):
>> E = 1,2,3,4,7,6,5,8,9,10,11,12,15,14,13,16,17,22,21,18,23,20,...
>>
>> Best,
>> É.
>>
>


-- 
Maximilian