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.

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A120167 a(n) = 9 + floor((3 + Sum_{j=1..n-1} a(j))/4).

Original entry on oeis.org

9, 12, 15, 18, 23, 29, 36, 45, 56, 70, 88, 110, 137, 171, 214, 268, 335, 418, 523, 654, 817, 1021, 1277, 1596, 1995, 2494, 3117, 3896, 4870, 6088, 7610, 9512, 11890, 14863, 18579, 23223, 29029, 36286, 45358, 56697
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Magma
    function f(n, a, b)
      t:=0;
        for k in [1..n-1] do
          t+:= a+Floor((b+t)/4);
        end for;
      return t;
    end function;
    g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
    A120167:= func< n | g(n, 9, 3) >;
    [A120167(n): n in [1..60]]; // G. C. Greubel, Sep 09 2023
    
  • Mathematica
    nxt[{t_,a_}]:=Module[{c=Floor[(39+t)/4]},{t+c,c}]; NestList[nxt,{9,9},40][[All,2]] (* Harvey P. Dale, Apr 24 2019 *)
  • SageMath
    @CachedFunction
    def f(n, p, q): return p + (q +sum(f(k, p, q) for k in range(1, n)))//4
    def A120167(n): return f(n, 9, 3)
    [A120167(n) for n in range(1, 61)] # G. C. Greubel, Sep 09 2023

A120168 a(n) = 11 + floor(Sum_{j-1..n-1} a(j)/4).

Original entry on oeis.org

11, 13, 17, 21, 26, 33, 41, 51, 64, 80, 100, 125, 156, 195, 244, 305, 381, 476, 595, 744, 930, 1163, 1453, 1817, 2271, 2839, 3548, 4435, 5544, 6930, 8663, 10828, 13535, 16919, 21149, 26436, 33045, 41306, 51633, 64541
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Magma
    function f(n, a, b)
      t:=0;
        for k in [1..n-1] do
          t+:= a+Floor((b+t)/4);
        end for;
      return t;
    end function;
    g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
    A120168:= func< n | g(n, 11, 0) >;
    [A120168(n): n in [1..60]]; // G. C. Greubel, Sep 09 2023
    
  • Mathematica
    f[n_, p_, q_]:= f[n,p,q]= p +Quotient[q +Sum[f[k,p,q], {k,n-1}], 4];
    A120168[n_]:= f[n, 11, 0];
    Table[A120168[n], {n, 60}] (* G. C. Greubel, Sep 09 2023 *)
  • SageMath
    @CachedFunction
    def f(n, p, q): return p + (q +sum(f(k, p, q) for k in range(1, n)))//4
    def A120168(n): return f(n, 11, 0)
    [A120168(n) for n in range(1, 61)] # G. C. Greubel, Sep 09 2023

A306470 a(0) = 0; for n > 0, if the number of blanks already in the sequence is greater than or equal to n, n is filled in at the n-th blank counting from the end of the sequence; otherwise n is added to the end of the sequence followed by n blanks.

Original entry on oeis.org

0, 1, 3, 2, 9, 5, 4, 120, 8, 14, 7, 6, 22, 13, 34, 12, 21, 11, 10, 52, 20, 33, 19, 79, 18, 32, 17, 51, 16, 15, 31, 181, 30, 50, 29, 78, 28, 49, 27, 119, 26, 48, 25, 77, 24, 23, 47, 615, 46, 76, 45, 118, 44, 75, 43, 180, 42, 74, 41, 117, 40, 73
Offset: 0

Views

Author

Jan Koornstra, Feb 17 2019

Keywords

Comments

The consecutive number of blanks added to the sequence (1, 2, 4, 6, 10, 15, ...) appear to form the sequence A112088 - 1. The unique values for the length of the sequence (1, 3, 6, 11, 18, 29, 45, 69, 105, ...) then becomes 1 + the partial sums of A112088.

Examples

			For n < 3, n is added to the sequence along with n blanks (denoted by -1): [0, 1, -1, 2, -1, -1]. There are now three blanks in the sequence, hence n = 3 is filled in at the third blank counting from the end of the sequence: [0, 1, 3, 2, -1, -1].
		

Crossrefs

Cf. A112088.

Programs

  • Mathematica
    TakeWhile[Nest[Function[{a, n, b}, If[b >= n, ReplacePart[a, Position[a, -1][[-n]] -> n ], Join[a, Prepend[ConstantArray[-1, n], n]]]] @@ {#, Max@ # + 1, Count[#, -1]} &, {0}, 10^3], # > -1 &] (* Michael De Vlieger, Mar 24 2019 *)
  • Python
    seq = [0]
    for n in range(1, 1387):
      num_blanks = seq.count(-1)
      if num_blanks >= n: seq[[index for index, value in enumerate(seq) if value == -1][num_blanks - n]] = n
      else: seq += [n] + [-1] * n
    print(seq[:100])

A120145 a(n) = 20 + floor( (1 + Sum_{j=1..n-1} a(j)) / 2 ).

Original entry on oeis.org

20, 30, 45, 68, 102, 153, 229, 344, 516, 774, 1161, 1741, 2612, 3918, 5877, 8815, 13223, 19834, 29751, 44627, 66940, 100410, 150615, 225923, 338884, 508326, 762489, 1143734, 1715601, 2573401, 3860102, 5790153, 8685229, 13027844
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:= a[n]= 20 +Quotient[1 +Sum[a[k], {k,n-1}], 2];
    Table[a[n], {n,60}] (* G. C. Greubel, May 14 2023 *)
  • SageMath
    @CachedFunction
    def A120145(n): return 20 + (1+sum(A120145(k) for k in range(1,n)))//2
    [A120145(n) for n in range(1,61)] # G. C. Greubel, May 14 2023

A120146 a(n) = 22 + floor( Sum_{j=1..n-1} a(j)/2 ).

Original entry on oeis.org

22, 33, 49, 74, 111, 166, 249, 374, 561, 841, 1262, 1893, 2839, 4259, 6388, 9582, 14373, 21560, 32340, 48510, 72765, 109147, 163721, 245581, 368372, 552558, 828837, 1243255, 1864883, 2797324, 4195986, 6293979, 9440969, 14161453
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

A120149 a(n) = 2 + floor((1 + Sum_{j=1..n-1} a(j))/3).

Original entry on oeis.org

2, 3, 4, 5, 7, 9, 12, 16, 21, 28, 38, 50, 67, 89, 119, 159, 212, 282, 376, 502, 669, 892, 1189, 1586, 2114, 2819, 3759, 5012, 6682, 8910, 11880, 15840, 21120, 28160, 37546, 50062, 66749, 88999, 118665, 158220, 210960, 281280, 375040, 500053, 666738
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    f[s_] := Append[s, Floor[(7 + Plus @@ s)/3]]; Nest[f, {2}, 44] (*  Robert G. Wilson v, Jul 08 2006 *)
  • SageMath
    @CachedFunction
    def A120149(n): return 2 + (1+sum(A120149(k) for k in range(1,n)))//3
    [A120149(n) for n in range(1, 61)] # G. C. Greubel, Jun 04 2023

Extensions

More terms from Robert G. Wilson v, Jul 08 2006

A120164 a(n) = 6 + floor( Sum_{j=1..n-1} a(j)/4 ).

Original entry on oeis.org

6, 7, 9, 11, 14, 17, 22, 27, 34, 42, 53, 66, 83, 103, 129, 161, 202, 252, 315, 394, 492, 615, 769, 961, 1202, 1502, 1878, 2347, 2934, 3667, 4584, 5730, 7163, 8953, 11192, 13990, 17487, 21859, 27324, 34155
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Magma
    function f(n, a, b)
      t:=0;
        for k in [1..n-1] do
          t+:= a+Floor((b+t)/4);
        end for;
      return t;
    end function;
    g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
    A120164:= func< n | g(n, 6, 0) >;
    [A120164(n): n in [1..60]]; // G. C. Greubel, Sep 05 2023
    
  • Mathematica
    f[n_, p_, q_]:= f[n, p, q]= p +Quotient[q +Sum[f[k,p,q], {k,n-1}], 4];
    A120164[n_]:= f[n,6,0];
    Table[A120164[n], {n, 60}] (* G. C. Greubel, Sep 05 2023 *)
  • SageMath
    @CachedFunction
    def f(n,p,q): return p + (q +sum(f(k,p,q) for k in range(1, n)))//4
    def A120164(n): return f(n, 6, 0)
    [A120164(n) for n in range(1, 61)] # G. C. Greubel, Sep 05 2023

A120165 a(n) = 7 + floor((1 + Sum_{j=1..n-1} a(j))/4).

Original entry on oeis.org

7, 9, 11, 14, 17, 21, 27, 33, 42, 52, 65, 81, 102, 127, 159, 199, 248, 310, 388, 485, 606, 758, 947, 1184, 1480, 1850, 2312, 2890, 3613, 4516, 5645, 7056, 8820, 11025, 13782, 17227, 21534, 26917, 33647, 42058
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Magma
    function f(n, a, b)
      t:=0;
        for k in [1..n-1] do
          t+:= a+Floor((b+t)/4);
        end for;
      return t;
    end function;
    g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
    A120165:= func< n | g(n, 7, 1) >;
    [A120165(n): n in [1..60]]; // G. C. Greubel, Sep 09 2023
    
  • Maple
    A[1]:= 7: S:= 7:
    for n from 2 to 100 do A[n]:= floor((29 + S)/4); S:= S + A[n] od:
    seq(A[i],i=1..100); # Robert Israel, Mar 20 2017
  • Mathematica
    a = {7}; Do[AppendTo[a, Floor[(29 + Total@ a)/4]], {i, 2, 40}]; a (* Michael De Vlieger, Mar 20 2017 *)
  • SageMath
    @CachedFunction
    def f(n, p, q): return p + (q +sum(f(k, p, q) for k in range(1, n)))//4
    def A120165(n): return f(n, 7, 1)
    [A120165(n) for n in range(1, 61)] # G. C. Greubel, Sep 09 2023

Formula

a(n) ~ c (5/4)^n with c approximately 5.5905081519. - Robert Israel, Mar 20 2017

A120171 a(n) = 2 + floor((1 + Sum_{j=1..n-1} a(j))/5).

Original entry on oeis.org

2, 2, 3, 3, 4, 5, 6, 7, 8, 10, 12, 14, 17, 20, 24, 29, 35, 42, 50, 60, 72, 87, 104, 125, 150, 180, 216, 259, 311, 373, 448, 537, 645, 774, 929, 1114, 1337, 1605, 1926, 2311, 2773, 3328, 3993, 4792, 5750, 6900, 8280, 9936, 11923, 14308, 17170, 20604, 24724, 29669
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Magma
    function f(n, a, b)
      t:=0;
        for k in [1..n-1] do
          t+:= a+Floor((b+t)/5);
        end for;
      return t;
    end function;
    g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
    A120171:= func< n | g(n, 2, 1) >;
    [A120171(n): n in [1..60]]; // G. C. Greubel, Dec 25 2023
    
  • Mathematica
    f[s_] := Append[s, Floor[(11 + Plus @@ s)/5]]; Nest[f, {2}, 53] (* Robert G. Wilson v, Jul 08 2006 *)
  • SageMath
    @CachedFunction
    def f(n, p, q): return p + (q +sum(f(k, p, q) for k in range(1, n)))//5
    def A120171(n): return f(n, 2, 1)
    [A120171(n) for n in range(1, 61)] # G. C. Greubel, Dec 25 2023

Extensions

More terms from Robert G. Wilson v, Jul 08 2006

A120184 a(1)=8; a(n)=floor((48+sum(a(1) to a(n-1)))/6).

Original entry on oeis.org

8, 9, 10, 12, 14, 16, 19, 22, 26, 30, 35, 41, 48, 56, 65, 76, 89, 104, 121, 141, 165, 192, 224, 261, 305, 356, 415, 484, 565, 659, 769, 897, 1047, 1221, 1425, 1662, 1939, 2262, 2639, 3079
Offset: 1

Views

Author

Graeme McRae, Jun 10 2006

Keywords

Crossrefs

Programs

  • Mathematica
    nxt[{t_,a_}]:=With[{c=Floor[(48+t)/6]},{t+c,c}]; NestList[nxt,{8,8},40][[All,2]] (* Harvey P. Dale, Apr 07 2019 *)
Previous Showing 21-30 of 79 results. Next