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.

A334666 For any number with binary expansion (b_1, ..., b_w), replace the i-th "1" by b_i for i = 1..A000120(n) and the j-th "0" by b_{w+1-j} for j = 1..A023416(n); the resulting binary expansion is that of a(n).

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 6, 7, 8, 12, 9, 13, 12, 14, 14, 15, 16, 24, 20, 28, 17, 25, 19, 27, 24, 28, 25, 29, 28, 30, 30, 31, 32, 48, 40, 56, 34, 50, 41, 57, 33, 49, 38, 54, 37, 53, 39, 55, 48, 56, 52, 60, 49, 57, 51, 59, 56, 60, 57, 61, 60, 62, 62, 63, 64, 96, 80
Offset: 0

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Author

Rémy Sigrist, May 07 2020

Keywords

Comments

Fixed points correspond to A023758.

Examples

			For n = 41:
- the binary representation of 41 is "101001",
- the 3 1's are replaced by 1, 0, 1, respectively,
- the 3 0's are replaced by 1, 0, 0, respectively,
- hence we obtain "110001",
- and a(41) = 49.
		

Crossrefs

See A334667 for a similar sequence.

Programs

  • PARI
    a(n) = { my (b=binary(n), t=vector(#b), l=0, r=#b+1); for (k=1, #b, t[k] = if (b[k], b[l++], b[r--])); fromdigits(t, 2) }

Formula

A000120(a(n)) = A000120(n).
A023416(a(n)) = A023416(n).