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.

A198192 Replace 2^k in the binary representation of n with n-k (i.e. if n = 2^a + 2^b + 2^c + ... then a(n) = (n-a) + (n-b) + (n-c) + ...).

Original entry on oeis.org

0, 1, 1, 5, 2, 8, 9, 18, 5, 15, 16, 29, 19, 34, 36, 54, 12, 30, 31, 52, 34, 57, 59, 85, 41, 68, 70, 100, 75, 107, 110, 145, 27, 61, 62, 99, 65, 104, 106, 148, 72, 115, 117, 163, 122, 170, 173, 224, 87, 138, 140, 194, 145, 201, 204, 263, 156, 216, 219, 282, 226
Offset: 0

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Author

Brian Reed, Oct 21 2011

Keywords

Examples

			a(5) = (5-2) + (5-0) = 8 because 5 = 2^2 + 2^0.
a(7) = (7-2) + (7-1) + (7-0) = 18 because 7 = 2^2 + 2^1 + 2^0.
		

Crossrefs

Programs

  • MATLAB
    % n is number of terms to be computed:
    function [B] = predAddition(n)
       for i = 0:n
          k = i;
          c = 0;
          s = 0;
          while(k ~= 0)
             if ((i - c) >= 0)
                s = s + mod(k,2)*(i-c);
             end
             c = c + 1;
             k = (k - mod(k,2))/2;
          end
          B(i+1) = s;
       end
    end
  • Maple
    b:= (n, k)-> `if`(n=0, 0, k*(n mod 2)+b(floor(n/2), k-1)):
    a:= n-> b(n, n):
    seq(a(n), n=0..100);  # Alois P. Heinz, Oct 25 2011

Formula

a(n) = n*A000120(n) - A073642(n). - Franklin T. Adams-Watters, Oct 22 2011
a(n) = b(n,n) with b(0,k) = 0, b(n,k) = k*(n mod 2) + b(floor(n/2),k-1) for n>0. - Alois P. Heinz, Oct 25 2011