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.

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A347196 Let c(k) be the infinite binary string 010111001... (A030308), the concatenation of reverse order integer binary words ( 0;1;01;11;001;101;... ). a(n) is the bit index k of the first occurrence of the reverse order binary word of n ( n = 2^0*c(a(n)) + 2^1*c(a(n)+1) + ... ).

Original entry on oeis.org

0, 1, 0, 3, 6, 1, 2, 3, 18, 5, 0, 8, 6, 1, 2, 13, 50, 17, 32, 4, 23, 9, 7, 29, 18, 5, 0, 37, 34, 1, 12, 13, 130, 49, 88, 16, 67, 31, 20, 3, 56, 22, 24, 8, 6, 38, 28, 84, 50, 17, 32, 4, 70, 9, 39, 36, 90, 33, 0, 40, 110, 11, 12, 43, 322, 129, 224, 48, 175, 87, 53, 15
Offset: 0

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Author

Thomas Scheuerle, Aug 22 2021

Keywords

Comments

It is not surprising to see dyadic self-similarity in the graph of this sequence. For example the graph of a(0..2^9) looks like a rescaled version of a(0..2^8). Each of these intervals reminds a bit of particle traces in a cloud chamber.

Examples

			pos:0,1,2,3,4,5,6,7,8,9,...
c:  0|1|0,1|1,1|0,0,1|1,0,1...
    0                           a(0) = 0
    . 1                         a(1) = 1
    0 1                         a(2) = 0
    . . . 1 1                   a(3) = 3
    . . . . . . 0 0 1           a(4) = 6
    . 1 0 1                     a(5) = 1
    . . 0 1 1                   a(6) = 2
		

Crossrefs

Programs

  • MATLAB
    function a = A347196( max_n)
        c = 0; a = 0;
        for n = 1:max_n
            b = bitget(n,1:64);
            c = [c b(1:find(b == 1, 1, 'last' ))];
        end
        for n = 1:max_n
            b = bitget(n,1:64);
            word = b(1:find(b == 1, 1, 'last' ));
            pos = strfind(c, word);
            a(n+1) = pos(1)-1;
        end
    end

Formula

a(n) <= Sum_{k=0..n} A070939(k).
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