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 1-10 of 14 results. Next

A138056 Levels of substitution A103684 (based on the morphism f: 1->{1,2}, 2->{1,3}, 3->{3}) like Markov substitution taken as polynomials p(x,n)]and coefficients of the differential polynomials returned as q(x,n) =dp(x,n)dx coefficients (first zero omitted).

Original entry on oeis.org

2, 2, 2, 9, 2, 2, 9, 4, 10, 6, 2, 2, 9, 4, 10, 6, 7, 16, 9, 30, 11, 24, 2, 2, 9, 4, 10, 6, 7, 16, 9, 30, 11, 24, 13, 28, 15, 48, 17, 36, 19, 20, 42, 22, 69, 2, 2, 9, 4, 10, 6, 7, 16, 9, 30, 11, 24, 13, 28, 15, 48, 17, 36, 19, 20, 42, 22, 69, 24, 50, 26, 81, 28, 58, 30, 31, 64, 33, 102, 35
Offset: 1

Views

Author

Roger L. Bagula, May 02 2008

Keywords

Examples

			{2},
{2, 2, 9},
{2, 2, 9, 4, 10, 6},
{2, 2, 9, 4, 10, 6, 7, 16, 9, 30, 11, 24},
{2, 2, 9, 4, 10, 6, 7, 16, 9, 30, 11, 24, 13, 28, 15, 48, 17, 36, 19, 20, 42, 22, 69},
{2, 2, 9, 4, 10, 6, 7, 16, 9, 30, 11, 24, 13, 28, 15, 48, 17, 36, 19, 20, 42, 22, 69, 24, 50, 26, 81, 28, 58, 30, 31, 64, 33, 102, 35, 72, 37, 76, 39, 120, 41, 84, 43}
		

Crossrefs

Cf. A103684.

Programs

  • Mathematica
    s[1] = {1, 2}; s[2] = {1, 3}; s[3] = {1};
    t[a_] := Flatten[s /@ a];
    p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]];
    (*A103684*);
    a = Table[p[n], {n, 0, 10}];
    Flatten[a];
    b = Table[CoefficientList[D[Apply[Plus, Table[a[[n]][[m]]*x^( m - 1), {m, 1, Length[a[[n]]]}]], x], x], {n, 1, 11}];
    Flatten[b]
    Table[Apply[Plus, CoefficientList[D[Apply[Plus, Table[a[[n]][[m]]* x^(m - 1), {m, 1, Length[a[[n]]]}]], x], x]], {n, 1, 11}];

A073058 Define s(1)={1,2}, s(2)={1,3} and s(3)={1}. For a finite sequence A={a_1, ..., a_n}, with elements in {1,2,3}, define t(A) to be the concatenation of A, s(a_1), s(a_2), ... and s(a_n). Start with the sequence {1,2,3} and repeatedly apply t; limiting sequence is shown.

Original entry on oeis.org

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

Views

Author

Roger L. Bagula, Aug 16 2002

Keywords

Comments

A fractal sequence related to a sequence of Rauzy.

Crossrefs

Programs

  • Mathematica
    Nest[ Flatten[ Join[#, # /. {1 -> {1, 2}, 2 -> {1, 3}, 3 -> {1}}]] &, {1, 2, 3},
    4] (* Robert G. Wilson v, Jan 01 2017 *)

A103685 Consider the morphism 1->{1,2}, 2->{1,3}, 3->{1}; a(n) is the total number of '3' after n substitutions.

Original entry on oeis.org

0, 0, 1, 5, 17, 51, 147, 419, 1191, 3383, 9607, 27279, 77455, 219919, 624415, 1772895, 5033759, 14292287, 40579903, 115217983, 327136895, 928835455, 2637230207, 7487852799, 21260161279, 60363694335, 171389837823, 486624896511, 1381667623423, 3922950583295
Offset: 0

Views

Author

Roger L. Bagula, Mar 26 2005

Keywords

Comments

Examples of the morphism starting with {1} are shown in A103684. Counting the total number of '1' in rows 1 to n of A103684 yields 1, 3, 8,... = A073357(n+1),
counting the total number of '2' in rows 1 to n yields 0, 1, 4,.. = A115390(n+1),
and counting the total number '3' in rows 1 to n yields a(n), the sequence here.
Inverse binomial transform yields 0, 0, 1, 2, 3, 6, 11, 20,..., a variant of A001590 [Nov 18 2010]

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5,-8,6,-2},{0,0,1,5},30] (* Harvey P. Dale, Nov 10 2011 *)

Formula

a(n)= +5*a(n-1) -8*a(n-2) +6*a(n-3) -2*a(n-4) = a(n-1)+A115390(n). [Nov 18 2010]
G.f.: x^2 / ( (x-1)*(2*x^3-4*x^2+4*x-1) ). [Nov 18 2010]

Extensions

Depleted by the information already in A073357 and A115390; corrected image of {2} in the defn. - The Assoc. Eds. of the OEIS, Nov 18 2010

A105111 Triangle read by rows, based on the morphism f: 1->2, 2->3, 3->{3,5,4}, 4->5, 5->6, 6->{6,2,1}. First row is 1. If current row is a,b,c,..., then the next row is a,b,c,...,f(a),f(b),f(c),...

Original entry on oeis.org

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

Views

Author

Roger L. Bagula, Apr 07 2005

Keywords

Comments

6-symbol substitution based on the second type Rauzy substitution that gives a tile in the Kenyon boundary method.

Crossrefs

Programs

  • Mathematica
    s[n_] := n /. {1 -> 2, 2 -> 3, 3 -> {3, 5, 4}, 4 -> 5, 5 -> 6, 6 -> {6, 2, 1}}; t[a_] := Join[a, Flatten[s /@ a]]; Flatten[ NestList[t, {1}, 5]]

A138060 Triangle read by rows: row 1 = {1}; for n>1, row n is obtained from row n-1 by applying the morphism 1->1,2; 2->3; 3->4; 4->1.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4
Offset: 1

Views

Author

Roger L. Bagula, May 02 2008

Keywords

Examples

			{1},
{1, 2},
{1, 2, 3},
{1, 2, 3, 4},
{1, 2, 3, 4, 1},
{1, 2, 3, 4, 1, 1, 2},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2},
{1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3, 4, 1, 1, 2, 1, 2, 3}
		

Crossrefs

Row sums are A138289. Rows converge to A138297.
Cf. A103684.

Programs

  • Mathematica
    SubstitutionSystem[{1 -> {1, 2}, 2 -> {3}, 3 -> {4}, 4 -> {1}}, {1}, 10] // Flatten (* Jean-François Alcover, Jul 01 2023 *)

Extensions

Edited by N. J. A. Sloane, May 06 2008

A105112 Triangle read by rows, based on the morphism f: 1->2, 2->3, 3->{3,5,5,4}, 4->5, 5->6, 6->{6,2,2,1}. First row is 1. If current row is a,b,c,..., then the next row is a,b,c,...,f(a),f(b),f(c),...

Original entry on oeis.org

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

Views

Author

Roger L. Bagula, Apr 07 2005

Keywords

Comments

Improved version of bi-Kenyon 6-symbol substitution.

Crossrefs

Cf. A103684.

Programs

  • Mathematica
    s[n_] := n /. {1 -> 2, 2 -> 3, 3 -> {3, 5, 5, 4}, 4 -> 5, 5 -> 6, 6 -> {6, 2, 2, 1}}; t[a_] := Join[a, Flatten[s /@ a]]; Flatten[ NestList[t, {1}, 5]]

A248335 A recursive sequence generated by an L-system defined in comments.

Original entry on oeis.org

1, 23, 3445, 45565667, 5667677867787889, 6778788978898990788989908990901, 7889899089909018990901901112899090190111290111211223, 89909019011129011121122390111211223112232323349011121122311223232334112232323342323343445
Offset: 1

Views

Author

Felix Fröhlich, Oct 26 2014

Keywords

Comments

The L-system producing the sequence is defined as follows:
Alphabet: 1 2 3 4 5 6 7 8 9 0
Initiator: 1
Production rules: (1 --> 23), (2 --> 34), (3 --> 45), (4 --> 56), (5 --> 67), (6 --> 78), (7 --> 89), (8 --> 90), (9 --> 1), (0 --> 12).

Crossrefs

A103956 A nonsense sequence.

Original entry on oeis.org

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

Views

Author

Roger L. Bagula, Mar 30 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Conway[1] = Conway[2] = 1;
    Conway[n_Integer?Positive] := Conway[n] = Conway[Conway[n - 1]] + Conway[n - Conway[n - 1]]
    s[1] = {1, 2}; s[2] = {1, 3}; s[3] = {1};
    t[a_] := Join[a, Flatten[s /@ a]];
    p[0] = {1}; p[1] = t[{1}];
    p[n_] := t[p[n - 1]]
    aa = Flatten[Table[p[If[n > 0, Conway[n], n]], {n, 0, 7}]]

Formula

1-> {1, 2} 2->{1, 3} 3->1 nested nest of substitution list are taken in a chaotic order.

A103957 A nonsense sequence.

Original entry on oeis.org

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

Views

Author

Roger L. Bagula, Mar 30 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Hofstadter[n_Integer? Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n - 1]] + Hofstadter[n - Hofstadter[n - 2]];
    Hofstadter[0] = Hofstadter[1] = 1;
    s[1] = {1, 2}; s[2] = {1, 3}; s[3] = {1};
    t[a_] := Join[a, Flatten[s /@ a]];
    p[0] = {1}; p[1] = t[{1}];
    p[n_] := t[p[n - 1]];
    Flatten[Table[p[If[n > 0, Hofstadter[n], n]], {n, 0, 7}]]

Formula

Involves substitutions 1-> {1, 2}, 2->{1, 3}, 3->1.

A105103 A bi-Rauzy Pisot substitution.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 6, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 6, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 6, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 6, 1, 2, 1, 3, 1, 2, 6, 1, 2, 1, 3, 1
Offset: 0

Views

Author

Roger L. Bagula, Apr 07 2005

Keywords

Crossrefs

Programs

  • Mathematica
    s[1] = {1, 2}; s[2] = {1, 3}; s[3] = {6}; s[4] = {4, 5}; s[5] = {4, 6}; s[6] = {1}; t[a_] := Join[a, Flatten[s /@ a]]; p[0] = {1}; p[1] = t[{1}]; p[n_] := t[p[n - 1]] aa = Flatten[Table[p[n], {n, 0, 6}]]

Formula

1->{1, 2} 2->{1, 3} 3->6 4->{4, 5} 5->{4, 6) 6->1
Showing 1-10 of 14 results. Next