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 1-7 of 7 results.

A010882 Period 3: repeat [1, 2, 3].

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Partial sums are given by A130481(n)+n+1. - Hieronymus Fischer, Jun 08 2007
41/333 = 0.123123123... - Eric Desbiaux, Nov 03 2008
Terms of the simple continued fraction for 3/(sqrt(37)-4). - Paolo P. Lava, Feb 16 2009
This is the lexicographically earliest sequence with no substring of more than 1 term being a palindrome. - Franklin T. Adams-Watters, Nov 24 2013

Crossrefs

Cf. A010872, A010873, A010874, A010875, A010876, A004526, A002264, A002265, A002266, A177036 (decimal expansion of (4+sqrt(37))/7), A214090.

Programs

Formula

G.f.: (1+2x+3x^2)/(1-x^3). - Paul Barry, May 25 2003
a(n) = 1 + (n mod 3). - Paolo P. Lava, Nov 21 2006
a(n) = A010872(n) + 1. - Hieronymus Fischer, Jun 08 2007
a(n) = 6 - a(n-1) - a(n-2) for n > 1. - Reinhard Zumkeller, Apr 13 2008
a(n) = n+1-3*floor(n/3) = floor(41*10^(n+1)/333)-floor(41*10^n/333)*10; a(n)-a(n-3)=0 with n>2. - Bruno Berselli, Jun 28 2010
a(n) = A180593(n+1)/3. - Reinhard Zumkeller, Oct 25 2010
a(n) = floor((4*n+3)/3) mod 4. - Gary Detlefs, May 15 2011
a(n) = -cos(2/3*Pi*n)-1/3*3^(1/2)*sin(2/3*Pi*n)+2. - Leonid Bedratyuk, May 13 2012
E.g.f.: 2*(3*exp(3*x/2) - sqrt(3)*cos(Pi/6-sqrt(3)*x/2))*exp(-x/2)/3. - Ilya Gutkovskiy, Jul 05 2016

A180592 Digital root of 2n.

Original entry on oeis.org

0, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, 3, 5, 7, 9, 2, 4, 6, 8, 1
Offset: 0

Views

Author

Odimar Fabeny, Sep 10 2010

Keywords

Comments

Period 9. - Robert G. Wilson v, Sep 20 2010
Also digital root of A002276(n). - Enrique Pérez Herrero, Nov 05 2022

Crossrefs

Programs

Formula

From R. J. Mathar, Nov 02 2010: (Start)
a(n) = A010888(2*n).
a(n) = a(n-9), n > 9.
G.f.: -x*(2 + 4*x + 6*x^2 + 8*x^3 + x^4 + 3*x^5 + 5*x^6 + 7*x^7 + 9*x^8) / ( (x-1)*(1 + x + x^2)*(x^6 + x^3 + 1) ). (End)

Extensions

More terms from Robert G. Wilson v, Sep 20 2010
Keyword:base and formulas from R. J. Mathar, Nov 02 2010

A180597 Digital root of 7n.

Original entry on oeis.org

0, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8
Offset: 0

Views

Author

Odimar Fabeny, Sep 10 2010

Keywords

Comments

Period of 9. - Robert G. Wilson v, Sep 20 2010

Crossrefs

Programs

Formula

G.f.: x*(7 + 5*x + 3*x^2 + x^3 + 8*x^4 + 6*x^5 + 4*x^6 + 2*x^7 + 9*x^8)/(1 - x^9). - Stefano Spezia, Apr 21 2022
a(n) = A010888(A008589(n)). - Michel Marcus, Apr 21 2022

Extensions

More terms from Robert G. Wilson v, Sep 20 2010

A180594 Digital root of 4n.

Original entry on oeis.org

0, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2, 6, 1, 5, 9, 4, 8, 3, 7, 2
Offset: 0

Views

Author

Odimar Fabeny, Sep 10 2010

Keywords

Comments

Period of 9. - Robert G. Wilson v, Sep 20 2010

Crossrefs

Programs

  • Mathematica
    f[n_] := Mod[4 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Sep 20 2010 *)
    Join[{0}, ReplaceAll[Table[Mod[4n, 9], {n, 99}], {0 -> 9}]] (* Alonso del Arte, Sep 23 2012 *)
    LinearRecurrence[{0,0,0,0,0,0,0,0,1},{0,4,8,3,7,2,6,1,5,9},120] (* or *) PadRight[ {0},120,{9,4,8,3,7,2,6,1,5}] (* Harvey P. Dale, Aug 09 2022 *)

Formula

G.f.: -x*(9*x^8+5*x^7+x^6+6*x^5+2*x^4+7*x^3+3*x^2+8*x+4)/((x-1)*(x^2+x+1)*(x^6+x^3+1)). - Colin Barker, Sep 23 2012

Extensions

More terms from Robert G. Wilson v, Sep 20 2010

A180595 Digital root of 5n.

Original entry on oeis.org

0, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 1, 6, 2, 7
Offset: 0

Views

Author

Odimar Fabeny, Sep 10 2010

Keywords

Comments

Period of 9. - Robert G. Wilson v, Sep 20 2010

Crossrefs

Programs

  • Mathematica
    f[n_] := Mod[5 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Sep 20 2010 *)
    Join[{0}, ReplaceAll[Table[Mod[5n, 9], {n, 99}], {0 -> 9}]] (* Alonso del Arte, Sep 23 2012 *)
    PadRight[{0},120,{9,5,1,6,2,7,3,8,4}] (* Harvey P. Dale, Jan 10 2024 *)

Formula

G.f.: -x*(9*x^8+4*x^7+8*x^6+3*x^5+7*x^4+2*x^3+6*x^2+x+5)/((x-1)*(x^2+x+1)*(x^6+x^3+1)). - Colin Barker, Sep 23 2012

Extensions

More terms from Robert G. Wilson v, Sep 20 2010

A180596 Digital root of 6n.

Original entry on oeis.org

0, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3, 9, 6, 3
Offset: 0

Views

Author

Odimar Fabeny, Sep 10 2010

Keywords

Comments

Period of 3. - Robert G. Wilson v, Sep 20 2010

Crossrefs

Programs

  • Mathematica
    f[n_] := Mod[6 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Sep 20 2010 *)
    PadRight[{0},120,{9,6,3}] (* Harvey P. Dale, Dec 18 2012 *)

Formula

G.f.: 3*x*(2 + x + 3*x^2)/(1 - x^3). - Stefano Spezia, Apr 21 2022
a(n) = A010888(A008588(n)). - Michel Marcus, Apr 24 2022

Extensions

More terms from Robert G. Wilson v, Sep 20 2010

A353109 Array read by antidiagonals: A(n, k) is the digital root of n*k with n >= 0 and k >= 0.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 3, 4, 3, 0, 0, 4, 6, 6, 4, 0, 0, 5, 8, 9, 8, 5, 0, 0, 6, 1, 3, 3, 1, 6, 0, 0, 7, 3, 6, 7, 6, 3, 7, 0, 0, 8, 5, 9, 2, 2, 9, 5, 8, 0, 0, 9, 7, 3, 6, 7, 6, 3, 7, 9, 0, 0, 1, 9, 6, 1, 3, 3, 1, 6, 9, 1, 0, 0, 2, 2, 9, 5, 8, 9, 8, 5, 9, 2, 2, 0
Offset: 0

Views

Author

Stefano Spezia, Apr 24 2022

Keywords

Examples

			The array begins:
    0, 0, 0, 0, 0, 0, 0, 0, ...
    0, 1, 2, 3, 4, 5, 6, 7, ...
    0, 2, 4, 6, 8, 1, 3, 5, ...
    0, 3, 6, 9, 3, 6, 9, 3, ...
    0, 4, 8, 3, 7, 2, 6, 1, ...
    0, 5, 1, 6, 2, 7, 3, 8, ...
    0, 6, 3, 9, 6, 3, 9, 6, ...
    0, 7, 5, 3, 1, 8, 6, 4, ...
    ...
		

Crossrefs

Cf. A003991, A004247, A010888, A056992 (diagonal), A073636, A139413, A180592, A180593, A180594, A180595, A180596, A180597, A180598, A180599, A303296, A336225, A353128 (antidiagonal sums), A353933, A353974 (partial sum of the main diagonal).

Programs

  • Mathematica
    A[i_,j_]:=If[i*j==0,0,1+Mod[i*j-1,9]];Flatten[Table[A[n-k,k],{n,0,12},{k,0,n}]]
  • PARI
    T(n,k) = if (n && k, (n*k-1)%9+1, 0); \\ Michel Marcus, May 12 2022

Formula

A(n, k) = A010888(A004247(n, k)).
A(n, k) = A010888(A003991(n, k)) for n*k > 0.
Showing 1-7 of 7 results.