A231925 - OEIS

%I #7 Nov 16 2013 14:15:35

%S 0,6,1,5,25,7,2,10,26,12,3,8,16,28,15,30,18,4,9,21,29,20,34,14,22,32,

%T 11,27,35,51,55,125,31,24,33,13,17,36,50,56,62,68,74,88,92,114,122,

%U 126,37,43,49,57,61,83,91,109,121,127,38,42,58,66,82,86,128,40,76,80

%N Terms of A231924 written in base 10: the binary expansions of a(n) and a(n+1) taken together can be rearranged to form a palindrome.

%C See A231924 for precise definition.

%C This is a permutation of the nonnegative integers - see the Comments in A228407 for the proof.

%t a[0] = 0; a[n_] := a[n] = Block[{k = 1, idm = IntegerDigits[ a[n - 1], 5], t = a@# & /@ Range[n - 1]}, Label[ start]; While[ MemberQ[t, k], k++];  While[ Select[ Permutations[ Join[ idm, IntegerDigits[k, 5]]], #[[1]] != 0 && # == Reverse@# &] == {}, k++; Goto[ start]]; k]; s = Array[a, 60, 0]

%Y Cf. A230892, A231921, A231923, A231927, A231929, A231931, A231933, A228407, A231924.

%K nonn,base,easy

%O 0,2

%A _N. J. A. Sloane_ and _Robert G. Wilson v_, Nov 15 2013