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 10 results.

A050032 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique value such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 3.

Original entry on oeis.org

1, 1, 3, 4, 7, 8, 11, 18, 29, 30, 33, 40, 51, 80, 113, 164, 277, 278, 281, 288, 299, 328, 361, 412, 525, 802, 1083, 1382, 1743, 2268, 3351, 5094, 8445, 8446, 8449, 8456, 8467, 8496, 8529, 8580, 8693, 8970, 9251, 9550, 9911, 10436
Offset: 1

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Author

Keywords

Crossrefs

Similar sequences with different initial conditions are A050024 (1,1,1), A050028 (1,1,2), A050036 (1,1,4), A050040 (1,2,1), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 1, 3][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
    end proc:
    seq(a(n), n = 1..60); # Petros Hadjicostas, Nov 14 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 1, 3}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050036 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 4.

Original entry on oeis.org

1, 1, 4, 5, 9, 10, 14, 23, 37, 38, 42, 51, 65, 102, 144, 209, 353, 354, 358, 367, 381, 418, 460, 525, 669, 1022, 1380, 1761, 2221, 2890, 4270, 6491, 10761, 10762, 10766, 10775, 10789, 10826, 10868, 10933, 11077, 11430, 11788
Offset: 1

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Author

Keywords

Crossrefs

Same as A050052 and A050068 except for second term.
Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050040 (1,2,1), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 1, 4][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
    end proc:
    seq(a(n), n = 1..60); # Petros Hadjicostas, Nov 14 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 1, 4}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050040 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 1.

Original entry on oeis.org

1, 2, 1, 2, 3, 4, 5, 8, 13, 14, 15, 18, 23, 36, 51, 74, 125, 126, 127, 130, 135, 148, 163, 186, 237, 362, 489, 624, 787, 1024, 1513, 2300, 3813, 3814, 3815, 3818, 3823, 3836, 3851, 3874, 3925, 4050, 4177, 4312, 4475, 4712, 5201
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 2, 1][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
    end proc:
    seq(a(n), n = 1..60); # Petros Hadjicostas, Nov 14 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 2, 1}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050044 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 2.

Original entry on oeis.org

1, 2, 2, 3, 5, 6, 8, 13, 21, 22, 24, 29, 37, 58, 82, 119, 201, 202, 204, 209, 217, 238, 262, 299, 381, 582, 786, 1003, 1265, 1646, 2432, 3697, 6129, 6130, 6132, 6137, 6145, 6166, 6190, 6227, 6309, 6510, 6714, 6931, 7193, 7574, 8360
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050040 (1,2,1), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 2, 2][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
    end proc:
    seq(a(n), n = 1..60); # Petros Hadjicostas, Nov 14 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 2, 2}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050048 a(n) = a(n-1) + a(m) for n >= 3, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = 2.

Original entry on oeis.org

1, 2, 3, 4, 7, 8, 11, 18, 29, 30, 33, 40, 51, 80, 113, 164, 277, 278, 281, 288, 299, 328, 361, 412, 525, 802, 1083, 1382, 1743, 2268, 3351, 5094, 8445, 8446, 8449, 8456, 8467, 8496, 8529, 8580, 8693, 8970, 9251, 9550, 9911, 10436
Offset: 1

Views

Author

Keywords

Comments

In the Mathematica program below, the author of the program uses the initial conditions a(1) = 1, a(2) = 2, and a(3) = 3. This is not necessary. We get the same sequence using the initial conditions a(1) = 1 and a(2) = 2. - Petros Hadjicostas, Nov 14 2019

Crossrefs

Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050040 (1,2,1), A050044 (1,2,2), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 3, [1, 2][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
    end proc:
    seq(a(n), n = 1..60); # Petros Hadjicostas, Nov 14 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 2, 3}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050056 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 1.

Original entry on oeis.org

1, 3, 1, 2, 3, 4, 5, 8, 13, 14, 15, 18, 23, 36, 51, 74, 125, 126, 127, 130, 135, 148, 163, 186, 237, 362, 489, 624, 787, 1024, 1513, 2300, 3813, 3814, 3815, 3818, 3823, 3836, 3851, 3874, 3925, 4050, 4177, 4312, 4475, 4712, 5201
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050040 (1,2,1), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050060 (1,3,2), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember; `if`(n < 4, [1, 3, 1][n],
           a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
         end proc:
    seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 15 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 3, 1}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

A050060 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 2.

Original entry on oeis.org

1, 3, 2, 3, 5, 6, 8, 13, 21, 22, 24, 29, 37, 58, 82, 119, 201, 202, 204, 209, 217, 238, 262, 299, 381, 582, 786, 1003, 1265, 1646, 2432, 3697, 6129, 6130, 6132, 6137, 6145, 6166, 6190, 6227, 6309, 6510, 6714, 6931, 7193, 7574, 8360
Offset: 1

Views

Author

Keywords

Comments

Variant of A050028 and A050044. - R. J. Mathar, Oct 15 2008

Crossrefs

Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050040 (1,2,1), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050064 (1,3,3), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 3, 2][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
    end proc:
    seq(a(n), n = 1..60); # Petros Hadjicostas, Nov 14 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 3, 2}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050064 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.

Original entry on oeis.org

1, 3, 3, 4, 7, 8, 11, 18, 29, 30, 33, 40, 51, 80, 113, 164, 277, 278, 281, 288, 299, 328, 361, 412, 525, 802, 1083, 1382, 1743, 2268, 3351, 5094, 8445, 8446, 8449, 8456, 8467, 8496, 8529, 8580, 8693, 8970, 9251, 9550, 9911, 10436
Offset: 1

Views

Author

Keywords

Comments

Variant of A050032 or A050048. - R. J. Mathar, Oct 15 2008

Crossrefs

Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050040 (1,2,1), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050068 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
         `if`(n < 4, [1, 3, 3][n], a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
         end proc:
    seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 18 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 3, 3}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 18 2019

A050068 a(n) = a(n-1) + a(m) for n >= 3, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = 3.

Original entry on oeis.org

1, 3, 4, 5, 9, 10, 14, 23, 37, 38, 42, 51, 65, 102, 144, 209, 353, 354, 358, 367, 381, 418, 460, 525, 669, 1022, 1380, 1761, 2221, 2890, 4270, 6491, 10761, 10762, 10766, 10775, 10789, 10826, 10868, 10933, 11077, 11430, 11788
Offset: 1

Views

Author

Keywords

Comments

The author of the Mathematica program below uses the initial conditions a(1) = 1, a(2) = 3, and a(3) = 4. This is not necessary. We get the same sequence by using the initial conditions a(1) = 1 and a(2) = 3. - Petros Hadjicostas, Nov 15 2019

Crossrefs

Same as A050036 and A050052 except for the second term.
Cf. similar sequences with different initial conditions: A050024 (1,1,1), A050028 (1,1,2), A050032 (1,1,3), A050036 (1,1,4), A050040 (1,2,1), A050044 (1,2,2), A050048 (1,2,3), A050052 (1,2,4), A050056 (1,3,1), A050060 (1,3,2), A050064 (1,3,3).

Programs

  • Maple
    a := proc(n) option remember; `if`(n < 3, [1,3][n],
            a(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3))
         end proc:
    seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 15 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 3, 4}, Flatten@Table[2 k - 1, {n, 5}, {k, 2^n}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 15 2019

A161187 Let S = A089237\{0} = union of primes and nonzero squares; sequence gives indices of squares.

Original entry on oeis.org

1, 4, 7, 10, 14, 17, 22, 26, 31, 35, 41, 46, 52, 58, 63, 70, 78, 84, 91, 98, 106, 114, 122, 129, 139, 148, 156, 165, 175, 184, 193, 204, 214, 225, 235, 246, 256, 266, 279, 291, 304, 316, 326, 339, 351, 365, 376, 390, 406, 417, 429, 445, 462, 475, 489, 501, 514
Offset: 1

Views

Author

Daniel Tisdale, Jun 06 2009

Keywords

Crossrefs

Cf. A089237. Complement of A161188.
Cf. A050052.

Programs

  • Haskell
    a161187 n = a161187_list !! (n-1)
    a161187_list = tail $ findIndices ((== 1) . a010052) a089237_list
    -- Reinhard Zumkeller, Dec 18 2012
    
  • Magma
    [1] cat [#PrimesUpTo(n^2-1)+n: n in [2..100]]; // Vincenzo Librandi, Feb 18 2016
    
  • Mathematica
    Table[PrimePi[n^2 - 1] + n, {n, 60}] (* Vincenzo Librandi, Feb 18 2016 *)
  • Python
    from sympy import primepi
    def A161187(n): return n+primepi(n**2) # Chai Wah Wu, Oct 12 2024

Formula

A089237(a(n)+1) = A000290(n). - Reinhard Zumkeller, Dec 18 2012

Extensions

Edited by N. J. A. Sloane, Jun 07 2009
Extended by Ray Chandler, May 06 2010
Showing 1-10 of 10 results.