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 1-3 of 3 results.

A003574 Order of 4 mod 4n-1.

Original entry on oeis.org

1, 3, 5, 2, 9, 11, 9, 5, 6, 6, 7, 23, 4, 10, 29, 3, 33, 35, 10, 39, 41, 14, 6, 18, 15, 51, 53, 18, 22, 12, 10, 7, 65, 18, 69, 30, 21, 15, 10, 26, 81, 83, 9, 30, 89, 30, 20, 95, 6, 99, 42, 33, 105, 14, 9, 37, 113, 15, 46, 119
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A003573. Second bisection of A053447.

Programs

  • GAP
    List([1..70],n->OrderMod(4,4*n-1)); # Muniru A Asiru, Feb 19 2019
    
  • Maple
    with(numtheory): f := n->order(4,4*n-1);
  • PARI
    a(n) = znorder(Mod(4, 4*n-1)); \\ Michel Marcus, Feb 22 2019

Formula

a(n) = A053447(2*n-1) for n >= 1. - Jianing Song, Oct 03 2022

A217852 Multiplicative order of 5 (mod 5*n - 1).

Original entry on oeis.org

1, 6, 6, 9, 2, 14, 16, 4, 5, 42, 18, 29, 16, 22, 36, 39, 6, 44, 46, 30, 4, 27, 18, 48, 3, 42, 22, 69, 12, 37, 30, 52, 20, 52, 14, 89, 22, 18, 96, 33, 16, 45, 106, 72, 24, 114, 12, 119, 30, 82, 42, 36, 10, 67, 136, 6, 5, 272, 42, 44, 36, 102, 156, 70, 54, 138, 166
Offset: 1

Views

Author

Arkadiusz Wesolowski, Nov 16 2012

Keywords

Comments

Least m such that 5*n - 1 divides 5^m - 1.

Crossrefs

Programs

  • GAP
    List([1..70],n->OrderMod(5,5*n-1)); # Muniru A Asiru, Feb 25 2019
  • Mathematica
    Table[MultiplicativeOrder[5, 5*n - 1], {n, 67}]
  • PARI
    vector(80, n, znorder(Mod(5, 5*n-1))) \\ Michel Marcus, Feb 09 2015
    

A119980 Order of the following permutation on 3n+1 symbols. Write the 3n+1 symbols horizontally into a 3-column grid and read them off vertically, i.e., column after column.

Original entry on oeis.org

1, 3, 6, 6, 11, 15, 52, 38, 51, 9, 360, 260, 35, 39, 364, 1932, 680, 532, 1122, 260, 2415, 3570, 168, 360, 71, 12285, 836, 12, 1680, 1155, 858, 936, 7956, 48300, 171120, 234, 4428, 235752, 712, 990, 119, 364182, 406, 11220, 412920, 25584, 476, 19998, 6486
Offset: 0

Views

Author

Roland Miyamoto, Aug 03 2006

Keywords

Examples

			For n=2, the grid with 0..6 by rows is
   0 1 2
   3 4 5      first column is one longer
   6
Reading them by columns gives (0,3,6,1,4,2,5) which as a permutation has order 6, so a(2) = 6.
		

Crossrefs

The case for 2 columns is A002326.
Cf. A003572.

Programs

  • GAP
    # GAP / KANT / KASH
    # SpartaEncrypt(d,L) returns the list M obtained by writing L in d columns
    # and then concatenating these columns
    SpartaEncrypt := function(d,L)
    local len, i, M;
    len := Length(L);
    M := [];
    for i in [1..d] do
    Append(M,L{[i,d+i..d*IntQuo(len-i,d)+i]});
    od;
    return M;
    end;
    # SpartaOrd(d,m) computes the order of SpartEncrypt(d,[0..m-1])
    # in the group S_m
    SpartaOrd := function(d,m)
    local L, M, i;
    M := [0..m-1];
    L := [0..m-1];
    i := 0;
    repeat
    i := i + 1;
    L := SpartaEncrypt(d,L);
    until L=M;
    return i;
    end;
    d:=3; r:=1;
    a := List([0..60],n->SpartaOrd(d,d*n+r));
    
  • PARI
    P(n,w,j)={my(c=j%w); if(c==0, j/w, j\w + c*n + 1)}
    Follow(s,f)={my(t=f(s), k=1); while(t>s, k++; t=f(t)); if(s==t, k, 0)}
    CyclePoly(n,w,x)={my(q=0); for(i=0, w*n, my(l=Follow(i, j->P(n,w,j))); if(l, q+=x^l)); q}
    a(n)={my(q=CyclePoly(n, 3, x), m=1); for(i=1, poldegree(q), if(polcoef(q, i), m=lcm(m, i))); m} \\ Andrew Howroyd, Jan 04 2024
Showing 1-3 of 3 results.