A231923 Terms of A231922 written in base 10: the binary expansions of a(n) and a(n+1) taken together can be rearranged to form a palindrome.

0, 5, 1, 4, 16, 6, 2, 8, 17, 10, 3, 7, 13, 19, 12, 20, 15, 21, 9, 18, 24, 33, 36, 64, 26, 31, 38, 41, 55, 61, 65, 22, 11, 14, 23, 29, 43, 46, 48, 53, 58, 63, 67, 27, 30, 39, 45, 54, 57, 66, 25, 32, 37, 42, 47, 59, 62, 68, 34, 40, 51, 60, 69, 28, 49, 52, 71, 35, 44, 50

Offset

0,2

Comments

See A231922 for precise definition.

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

Links

Table of n, a(n) for n=0..69.

Mathematica

a[0] = 0; a[n_] := a[n] = Block[{k = 1, idm = IntegerDigits[ a[n - 1], 4], t = a@# & /@ Range[n - 1]}, Label[ start]; While[ MemberQ[t, k], k++];  While[ Select[ Permutations[ Join[ idm, IntegerDigits[k, 4]]], #[[1]] != 0 && # == Reverse@# &] == {}, k++; Goto[ start]]; k]; s = Array[a, 60, 0]

Crossrefs

Cf. A230892, A231921, A231925, A231927, A231929, A231931, A231933, A228407, A231922.

Sequence in context: A286593 A242376 A307393 * A105664 A094882 A019840

Adjacent sequences: A231920 A231921 A231922 * A231924 A231925 A231926

Keyword

nonn,base,easy

Author

N. J. A. Sloane and Robert G. Wilson v, Nov 15 2013

Status

approved