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A187871 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. 0

%I

%S 1,12,123,1234,14325,143256,1234765,12347658,123476589,10123476589

%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

%O 1,2

%A _N. J. A. Sloane_, Mar 14 2011

%E a(6) to a(10) from Claudio Meller, Mar 14 2011

%E a(10) corrected by _Nathaniel Johnston_, Mar 15 2011

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Last modified April 15 07:59 EDT 2021. Contains 342975 sequences. (Running on oeis4.)