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%I #24 Nov 29 2021 01:39:37
%S 1,12,123,1234,14325,143256,1234765,12347658,123476589,10123476589,
%T 1103211658947,101121123476589,11013432111276589,1011211231458941367,
%U 110134151432111276589,10112112151431613476589,1101316151417121123476589,101121118131615141723476589
%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>.
%H Rémy Sigrist, <a href="/A187871/a187871.gp.txt">PARI program for A187871</a>
%o (PARI) See Links section.
%Y Cf. A051237, A187869.
%K nonn,base
%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
%E More terms from _Rémy Sigrist_, Nov 28 2021
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