%I #6 Feb 19 2014 14:10:40

%S 2,3,4,5,6,7,6,5,4,3,2,1,2,3,4,5,6,7,8,7,6,5,4,3,2,3,4,5,6,7,8,7,6,5,

%T 4,3,2,1,2,3,4,5,6,7,8,7,6,5,4,3,2,3,4,5,6,7,8,7,6,5,4,5,6,7,8,9,8,7,

%U 6,5,4,3,2,1,0,1,2,3,4,5,4,3,2,3,4,5,4

%N A walk based on the digits of E = exp(1) (A001113).

%C E = 2.718281828459045...

%C Between 2 and 7 we place 3, 4, 5 and 6.

%C Between 7 and 1 we place 6, 5, 4, 3 and 2.

%C Between 1 and 8 we place 2, 3, 4, 5, 6 and 7.

%C Between 8 and 2 we place 7, 6, 5, 4 and 3, and so on.

%C This gives:

%C 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 8, 7, 6, 5, 4, ...

%C This could be called a walk (or promenade) on the digits of E.

%t wbe[{a_,b_}]:=Rest[If[b>a,Range[a,b],Range[a,b,-1]]]; Join[{2},Flatten[ wbe/@ Partition[RealDigits[E,10,20][[1]],2,1]]] (* _Harvey P. Dale_, Feb 19 2014 *)

%Y Cf. A001113

%K nonn,easy,base

%O 1,1

%A _Philippe Deléham_, Nov 20 2013 at the suggestion of _N. J. A. Sloane_