A037884 a(n)=(1/2)*Sum{|d(i)-e(i)|} where Sum{d(i)*7^i} is the base 7 representation of n and e(i) are the digits d(i) in nondecreasing order.

0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 0, 0, 0, 1, 2, 3, 4, 0, 0, 0, 0, 1, 2, 3, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 0, 0, 1, 2, 3, 4, 5, 1, 1, 1, 2, 3, 4, 5, 2, 2, 2, 2, 3, 4, 5, 3, 3, 3, 3, 3, 4, 5, 4, 4, 4, 4, 4, 4, 5

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Programs

Maple

A037884 := proc(n)
    local a,dgs,dgsE ;
    a := 0 ;
    dgs := convert(n,base,7);
    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

Extensions

Definition swapped with A037875. - R. J. Mathar, Oct 19 2015