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.

A331193 Numbers whose binary and dual Zeckendorf representations are both palindromic.

Original entry on oeis.org

0, 1, 3, 33, 231, 255, 891, 3687, 21477, 1216041, 5360069, 418964451, 443750859, 1445812789, 23577810421, 25474675645, 154292473329, 1904542477755, 1925488579591, 9617724354513, 16654480398927, 169215938357145, 2563713753111945, 3408057776446851, 4019397080882727
Offset: 1

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Author

Amiram Eldar, Jan 11 2020

Keywords

Examples

			3 is a term since both its binary and dual Zeckendorf representations are 11 which is palindromic.
33 is a term since its binary representation, 100001, and its dual Zeckendorf representation, 1010101, are both palindromic.
		

Crossrefs

Intersection of A006995 and A331191.

Programs

  • Mathematica
    mirror[dig_, s_] := Join[dig, s, Reverse[dig]];
    select[v_, mid_] := Select[v, Length[#] == 0 || Last[#] != mid &];
    fib[dig_] := Plus @@ (dig * Fibonacci[Range[2, Length[dig] + 1]]);
    pals = Join[{{}}, Rest[Select[IntegerDigits /@ FromDigits /@ Tuples[{0, 1}, 22], SequenceCount[#, {0, 0}] == 0 &]]];
    dualZeckPals = Union @ Join[{0}, fib /@ Join[mirror[#, {}] & /@ (select[pals, 0]), mirror[#, {0}] & /@ (select[pals, 0]), mirror[#, {1}] & /@ pals]];
    binPalQ[n_] := PalindromeQ@IntegerDigits[n, 2]; Select[dualZeckPals, binPalQ]

Extensions

a(18)-a(22) from Chai Wah Wu, Jan 12 2020
a(23)-a(25) from Chai Wah Wu, Jan 13 2020