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.

Showing 1-2 of 2 results.

A269733 First differences of A269729.

Original entry on oeis.org

1, 1, 1, 1, 3, 3, -5, 3, 3, -5, 3, 3, 8, 8, -13, 8, 8, -13, 8, -13, 8, 8, -13, 8, 8, -13, 8, -13, 8, 8, -13, 8, 8, 21, 21, -34, 21, 21, -34, 21, -34, 21, 21, -34, 21, 21, -34, 21, -34, 21, 21, -34, 21, -34, 21, 21, -34, 21, 21, -34, 21, -34, 21, 21, -34, 21, 21, -34, 21, -34, 21, 21, -34, 21, -34, 21, 21, -34, 21, 21
Offset: 0

Views

Author

N. J. A. Sloane, Mar 08 2016

Keywords

Comments

John Conway remarks that he can explain why the terms of this sequence are (up to sign) Fibonacci numbers.

References

  • J. H. Conway, Postings to Math Fun Mailing List, Nov 25 1996 and Dec 02 1996.

Crossrefs

Cf. A269729.

Programs

Extensions

More terms from R. J. Mathar, May 08 2019

A269725 a(n) = row number of extended Wythoff array (see A035513) which contains the sequence n times the Fibonacci numbers 1,2,3,5,8,13,21,... .

Original entry on oeis.org

0, 2, 3, 4, 15, 18, 21, 24, 27, 30, 33, 96, 104, 112, 120, 128, 136, 144, 152, 160, 168, 176, 184, 192, 200, 208, 216, 224, 232, 630, 651, 672, 693, 714, 735, 756, 777, 798, 819, 840, 861, 882, 903, 924, 945, 966, 987, 1008, 1029, 1050, 1071, 1092, 1113, 1134, 1155, 1176, 1197, 1218, 1239, 1260
Offset: 1

Views

Author

N. J. A. Sloane, Mar 07 2016

Keywords

Examples

			Take n=5: 5 times 1,2,3,5,8,13,... gives 5,10,15,25,40,65,.., which is row 15 of the extended Wythoff array (when extended to the left), so a(5) = 15.
		

References

  • J. H. Conway, Posting to Math Fun Mailing List, Nov 25 1996.

Crossrefs

Programs

  • Maple
    A269725 := proc(n)
        local f,sl,r,c,wrks ;
        f := [seq(n*combinat[fibonacci](i),i=2..30)] ;
        for sl from 0 do
            for r from 1 do
                if A035513(r,1) = op(1+sl,f) then
                    wrks := true;
                    for c from 2 to 5 do
                        if A035513(r,c) <> op(c+sl,f) then
                            wrks := false;
                        end if;
                    end do:
                    if wrks then
                        print(n,f,r) ;
                        return r-1 ;
                    end if;
                elif A035513(r,1) > op(1+sl,f) then
                    break ;
                end if;
            end do:
        end do:
    end proc: # R. J. Mathar, May 06 2017
  • Mathematica
    W[n_, k_] := Fibonacci[k+1] Floor[n*GoldenRatio] + (n-1) Fibonacci[k];
    a[n_] := Module[{f, sl, r, c, wrks}, f = Table[n*Fibonacci[i], {i, 2, 30}]; For[sl = 0, True, sl++, For[r = 1, True, r++, Which[W[r, 1] == f[[1 + sl]], wrks = True; For[c = 2, c <= 5, c++, If[W[r, c] != f[[c+sl]], wrks = False]]; If[wrks, Return[r-1]], W[r, 1] > f[[1+sl]], Break[]]]]];
    Table[a[n], {n, 1, 60}] (* Jean-François Alcover, Sep 13 2022, after R. J. Mathar *)

Formula

a(n) = A173027(n)-1. - R. J. Mathar, May 06 2017
Showing 1-2 of 2 results.