%I #5 Dec 05 2013 19:56:35
%S 1,21,132,2431,13542,246531,1357642,24687531,135798642,24681097531,
%T 1357911108642,246810121197531,13579111312108642,2468101214131197531,
%U 135791113151412108642,24681012141615131197531
%N Begin with n and place (n-1) on the least significant side, place (n-2) on the most significant side and so on until a 1 is placed.
%e a(6)= 246531, the steps are 6 -> 65 -> 465 -> 4653 -> 24653 -> 246531.
%t f[n_] := Block[{j = 1, k = n - 1, d = IntegerDigits[n]}, While[k > 0, If[ EvenQ[j], d = Join[ IntegerDigits[k], d], d = Join[d, IntegerDigits[k]]]; j++; k-- ]; FromDigits[d]]; Table[ f[n], {n, 17}]
%Y Cf. A089370.
%K base,easy,nonn
%O 1,2
%A _Amarnath Murthy_, Nov 08 2003
%E More terms from _Robert G. Wilson v_, Nov 08 2003