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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. 7
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 (list; graph; refs; listen; history; text; internal format)
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
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
Sequence in context: A286593 A242376 A307393 * A105664 A094882 A019840
KEYWORD
nonn,base,easy
AUTHOR
STATUS
approved

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Last modified May 23 18:59 EDT 2024. Contains 372765 sequences. (Running on oeis4.)