[seqfan] Re: A187871
Alexander P-sky
apovolot at gmail.com
Tue Mar 15 18:12:57 CET 2011
Re: A187871
>Meller's term, 11032567498, is smaller than your 12347658910
Though it is obvious, perhaps it is worth to add to the definition that
a(n+1) is the minimal integer number, which complies with the condition
a(n+1) > a(n)
On 3/15/11, N. J. A. Sloane <njas at research.att.com> wrote:
> Peter, I admit I made a mistake in my definition of A187871.
> Here is a corrected version (in the internal format):
>
> %I
> %S 1,12,123,1234,14325,143256,1234765,12347658,123476589,11032567498
> %N a(1)=1; for n > 1, a(n) is the smallest number that is formed by
> arranging the decimal numbers "1", "2", ..., "n" in some order so that the
> sum of every pair of adjacent numbers "i" "j" is prime.
> %C A051237 and A187869 are the sequence that result if in addition we
> require that the number begins with "1" and ends with "n".
> %H Claudio Meller, <a
> href="http://www.misacertijos.com.ar/2011/03/lineas-con-numeros-de-1-n.html">Lineas
> con numeros de 1 a n</a>.
> %Y Cf. A051237, A187869.
> %K nonn,base,more,changed
> %O 1,2
> %A N. J. A. Sloane (njas(AT)research.att.com), Mar 14 2011
> %E a(6) to a(10) from Claudio Meller, Mar 14 2011
>
> You sent a b-file for this. You version begins:
>
> 1,12,123,1234,14325,143256,1234765,12347658,123476589,12347658910,1234710985611,
123476512118910,12347651211891013,1234761310981112514,123476512118151491013,
12347651211891013161514,1234765891013161514171211,123476589101316151417121118
>
> The difference is in the 10th term. Meller's term, 11032567498, is smaller
> than your 12347658910, so yours is a different sequence. Can you tell
> me exactly how you defined your version?
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