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.

A022414 Kim-sums: "Kimberling sums" K_n + K_3.

Original entry on oeis.org

2, 7, 10, 4, 15, 18, 20, 23, 9, 28, 31, 12, 36, 39, 41, 44, 17, 49, 52, 54, 57, 22, 62, 65, 25, 70, 73, 75, 78, 30, 83, 86, 33, 91, 94, 96, 99, 38, 104, 107, 109, 112, 43, 117, 120, 46, 125, 128, 130, 133, 51, 138, 141, 143, 146, 56, 151, 154, 59, 159, 162, 164, 167
Offset: 0

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Comments

Let W(i,j) denote the index of that row of the extended Wythoff array (see A035513) that contains the sequence formed by the sum of rows i and j. Then a(n) = W(2,n). - N. J. A. Sloane, Mar 07 2016

References

  • J. H. Conway, Posting to Math Fun Mailing List, Dec 02 1996.
  • M. LeBrun, Posting to Math Fun Mailing List Jan 10 1997.

Crossrefs

The "Kim-sums" K_n + K_i for i = 2 through 12 are given in A022413, A022414, A022415, A022416, ..., A022423.

Programs

  • Maple
    Ki := proc(n,i)
            option remember;
            local phi ;
            phi := (1+sqrt(5))/2 ;
            if i= 0 then
                    n;
            elif i=1 then
                    floor((n+1)*phi) ;
            else
                    procname(n,i-1)+procname(n,i-2) ;
            end if;
    end proc:
    Kisum := proc(n,m)
            local ks,a,i;
            ks := [seq( Ki(n,i)+Ki(m,i),i=0..5)] ;
            for i from 0 to 2 do
                    for a from 0 do
                            if Ki(a,0) = ks[i+1] and Ki(a,1) = ks[i+2] then
                                    return a;
                            end if;
                            if Ki(a,0) > ks[i+1] then
                                    break;
                            end if;
                    end do:
            end do:
    end proc:
    A022414 := proc(n)
        if n = 0 then
            2;
        else
                Kisum(n-1,2) ;
        end if;
    end proc:
    seq(A022414(i),i=0..80) ; # R. J. Mathar, Sep 03 2016
  • Mathematica
    Ki[n_, i_] := Ki[n, i] = Which[i == 0, n, i == 1, Floor[(n + 1)* GoldenRatio], True, Ki[n, i - 1] + Ki[n, i - 2]];
    Kisum [n_, m_] := Module[{ks, a, i}, ks = Table[Ki[n, i] + Ki[m, i], {i, 0, 5}]; For[i = 0, i <= 2, i++, For[a = 0, True, a++, If[Ki[a, 0] == ks[[i + 1]] && Ki[a, 1] == ks[[i + 2]], Return@a]; If[Ki[a, 0] > ks[[i + 1]], Break[]]]]];
    a[n_] := If[n == 0, 2, Kisum[n - 1, 2]];
    Table[a[n], {n, 0, 80}] (* Jean-François Alcover, Oct 15 2023, after R. J. Mathar *)