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.

A354901 a(n) = (b(2n) - 1)/2 - n for n > 0. To get b(n) start with A = n and then for i = 0..f(n) apply A := A + 2^i*T(A, f(n) - i) where T(n, k) = floor(n/2^k) mod 2 and f(n) = A000523(n).

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 5, 8, 12, 10, 14, 13, 11, 15, 9, 16, 24, 20, 28, 22, 30, 18, 26, 25, 21, 29, 23, 31, 19, 27, 17, 32, 48, 40, 56, 36, 52, 44, 60, 42, 58, 38, 54, 46, 62, 34, 50, 49, 41, 57, 37, 53, 45, 61, 43, 59, 39, 55, 47, 63, 35, 51, 33, 64, 96, 80, 112
Offset: 1

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Author

Mikhail Kurkov, Jun 11 2022

Keywords

Comments

Subsequences from a(2^m) to a(2^(m+1) - 1) for m >= 0 contain all numbers k such that 2^m <= k < 2^(m+1). This fact was proved (see Peter J. Taylor link).

Crossrefs

Programs

  • PARI
    b(n)=my(L=logint(n,2),A=n); for(i=0,L, A+=2^i*bittest(A,L-i)); A;
    a(n)=(b(2*n) - 1)/2 - n