A110095: non prime first differences
Alec Mihailovs
alec at mihailovs.com
Wed Sep 7 03:07:56 CEST 2005
Alexandre Wajnberg wrote,
> This seq (this little handmade part!) seems to be reducible to
> concatenated substrings
> a == 1 1 4 and
> b == 1 1 1 1 4 4 :
>
> (1 8 1 4) a a a b a a a b b a b...
>
> I wonder
> -if it's very the case (may be are there further other substrings of 1's
> and 4's);
> -if there are super patterns in there, or possible regroupings of aaab's
> and bab's?
It is easy to see that the positive integers that are not in A110095, are
2,3,..., 8 and series of 3 consecutive numbers p, p+1, p+2 where p is a
prime number such that p-2 is not prime (for every such p). Since there are
sequences of consecutive non-prime numbers of length >=N-1, for example,
N!+2,...N!+N for any N>1, the sequence of differences of A110095 contains
subsequences 1,1,...,1 of length >=N-1 for any N>1.
Alec Mihailovs
http://math.tntech.edu/alec/
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