cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A231933 Terms of A231932 written in base 10: the binary expansions of a(n) and a(n+1) taken together can be rearranged to form a palindrome.

Original entry on oeis.org

0, 10, 1, 9, 81, 11, 2, 18, 82, 20, 3, 12, 28, 84, 27, 90, 30, 4, 13, 37, 85, 36, 94, 22, 38, 92, 19, 83, 99, 163, 171, 729, 86, 14, 5, 23, 47, 95, 32, 48, 93, 21, 29, 100, 24, 6, 15, 55, 87, 54, 96, 33, 57, 109, 31, 39, 112, 120, 256, 280, 336, 352, 732, 91, 16, 7, 25
Offset: 0

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Keywords

Comments

See A231931 for precise definition.
This is a permutation of the nonnegative integers - see the Comments in A228407 for the proof.

Crossrefs

Programs

  • Mathematica
    a[0] = 0; a[n_] := a[n] = Block[{k = 1, idm = IntegerDigits[ a[n - 1], 9], t = a@# & /@ Range[n - 1]}, Label[ start]; While[ MemberQ[t, k], k++];  While[ Select[ Permutations[ Join[ idm, IntegerDigits[k, 9]]], #[[1]] != 0 && # == Reverse@# &] == {}, k++; Goto[ start]]; k]; s = Array[a, 60, 0]