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.

A037879 a(n) = (1/2)*Sum{|d(i)-e(i)|} where Sum{d(i)*2^i} is the base-2 representation of n and {e(i)} are digits {d(i)} in nondecreasing order.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 0, 1, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 1, 2, 2, 2, 1, 1, 1
Offset: 1

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Programs

  • Maple
    A037879 := proc(n)
            local a,dgs,dgsE ;
            a := 0 ;
            dgs := convert(n,base,2);
            dgsE := sort(dgs) ;
            for i from 1 to nops(dgs) do
                    a := a+ abs(op(i,dgs)-op(i,dgsE)) ;
            end do:
            a/2 ;
    end proc: # R. J. Mathar, Oct 19 2015

Formula

a(2*n) = a(n). a(2*n+1) is either a(n) or a(n) + 1. - Robert Israel, Feb 08 2019

Extensions

Definition swapped with A037870. - R. J. Mathar, Oct 19 2015