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 13 results. Next

A096118 Duplicate of A050029.

Original entry on oeis.org

1, 1, 2, 3, 4, 7, 9, 10, 11, 21, 30, 37, 41, 44, 46, 47, 48, 95, 141, 185, 226, 263, 293, 314
Offset: 1

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Author

Keywords

A096119 A050029(2^n + 1).

Original entry on oeis.org

1, 2, 4, 11, 48, 362, 5030, 133924, 6977521, 719087781, 147394353130, 60255915944715, 49197429536084417, 80280819225274033666, 261914438169525117048056
Offset: 0

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Author

Amarnath Murthy, Jul 01 2004

Keywords

Extensions

Extended and description corrected by Antti Karttunen, Aug 25 2006

A050049 a(n) = a(n-1) + a(m) for n >= 3, where m = 2^(p+1) + 2 - n 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, 5, 6, 11, 14, 16, 17, 33, 47, 58, 64, 69, 72, 74, 75, 149, 221, 290, 354, 412, 459, 492, 509, 525, 539, 550, 556, 561, 564, 566, 567, 1133, 1697, 2258, 2814, 3364, 3903, 4428, 4937, 5429, 5888, 6300, 6654, 6944, 7165, 7314
Offset: 1

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Author

Keywords

Comments

a(1) = 1 and a(2) = 2; subsequent terms are generated like this: if a(s) is the last term available, say a(2), then a(s+1) = a(s) + a(s-1), a(s+2) = a(s) + a(s-1) + a(s-2), ..., a(2*s-1) = a(s) + a(s-1) + a(s-2) + ... + a(2) + a(1), a(2*s) = a(2*s-1) + a(2*s-2), and so on. - Amarnath Murthy, Aug 01 2005
From Petros Hadjicostas, Nov 13 2019: (Start)
We explain further the process introduced by Amarnath Murthy above. The terms a(s) that are the "last term[s] available" are those that correspond to s = A000051(k) = 2^k + 1 for k >= 0. Thus, they are the terms a(2), a(3), a(5), a(9), a(17), a(33), and so on. See the example below.
In the Mathematica program below, the author of the program starts with a(1) = 1, a(2) = 2, and a(3) = 3, but that is not necessary. We may start with a(1) = 1 and a(2) = 2 and still get the same sequence. (End)

Examples

			From _Petros Hadjicostas_, Nov 13 2019: (Start)
We explain _Amarnath Murthy_'s process (see the Comments above).
a(3) = a(2) + a(1) = 3. [Now a(3) is the last term available.]
a(4) = a(3) + a(2) = 5.
a(5) = a(3) + a(2) + a(1) = 6. [Now a(5) is the last term available.]
a(6) = a(5) + a(4) = 11.
a(7) = a(5) + a(4) + a(3) = 14.
a(8) = a(5) + a(4) + a(3) + a(2) = 16.
a(9) = a(5) + ... + a(1) = 17. [Now a(9) is the last term available.]
a(10) = a(9) + a(8) = 33.
a(11) = a(9) + a(8) + a(7) = 47.
...
a(17) = a(9) + a(8) + ... + a(1) = 75. [Now a(17) is the last term available.]
a(18) = a(17) + a(16) = 149. (End)
		

Crossrefs

Cf. A000051 (index of "available" terms as described above), A110428 (a multiplicative version of this sequence).
Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050037 (1,1,4), A050041 (1,2,1), A050045 (1,2,2), A050053 (1,2,4), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3), A050069 (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)); end proc;
    seq(a(n), n = 1..50); # Petros Hadjicostas, Nov 13 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 2, 3}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 13 2019

A050069 a(n) = a(n-1) + a(m) for n >= 3, where m = 2^(p+1) + 2 - n 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, 7, 8, 15, 19, 22, 23, 45, 64, 79, 87, 94, 98, 101, 102, 203, 301, 395, 482, 561, 625, 670, 693, 715, 734, 749, 757, 764, 768, 771, 772, 1543, 2311, 3075, 3832, 4581, 5315, 6030, 6723, 7393, 8018, 8579, 9061, 9456, 9757
Offset: 1

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Author

Keywords

Comments

In the Mathematica program below, the author of the program uses a(1) = 1, a(2) = 3, and a(3) = 4 as initial conditions. This is not necessary. We get the same sequence using only a(1) = 1 and a(2) = 3 as initial conditions. - Petros Hadjicostas, Nov 13 2019

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050037 (1,1,4), A050041 (1,2,1), A050045 (1,2,2), A050049 (1,2,3), A050053 (1,2,4), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 3, [1, 3][n], a(n - 1) + a(Bits:-Iff(n - 2, n - 2) + 3 - n)); end proc;
    seq(a(n), n = 1 .. 48); # Petros Hadjicostas, Nov 08 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 3, 4}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 08 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 08 2019

A050033 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer 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, 5, 9, 12, 13, 14, 27, 39, 48, 53, 57, 60, 61, 62, 123, 183, 240, 293, 341, 380, 407, 421, 434, 446, 455, 460, 464, 467, 468, 469, 937, 1404, 1868, 2328, 2783, 3229, 3663, 4084, 4491, 4871, 5212, 5505, 5745, 5928, 6051
Offset: 1

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Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050037 (1,1,4), A050041 (1,2,1), A050045 (1,2,2), A050049 (1,2,3), A050053 (1,2,4), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3), A050069 (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)); end proc;
    seq(a(n), n = 1 .. 48); # Petros Hadjicostas, Nov 08 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 1, 3}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 08 2019

A050037 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 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, 6, 11, 15, 16, 17, 33, 48, 59, 65, 70, 74, 75, 76, 151, 225, 295, 360, 419, 467, 500, 517, 533, 548, 559, 565, 570, 574, 575, 576, 1151, 1725, 2295, 2860, 3419, 3967, 4500, 5017, 5517, 5984, 6403, 6763, 7058, 7283, 7434
Offset: 1

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Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050041 (1,2,1), A050045 (1,2,2), A050049 (1,2,3), A050053 (1,2,4), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3), A050069 (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)); end proc;
    seq(a(n), n = 1 .. 48); # Petros Hadjicostas, Nov 08 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 1, 4}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 08 2019

A050041 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n 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, 3, 4, 7, 8, 10, 11, 21, 29, 36, 40, 43, 44, 46, 47, 93, 137, 180, 220, 256, 285, 306, 317, 327, 335, 342, 346, 349, 350, 352, 353, 705, 1055, 1404, 1750, 2092, 2427, 2754, 3071, 3377, 3662, 3918, 4138, 4318, 4455, 4548, 4595
Offset: 1

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Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050037 (1,1,4), A050045 (1,2,2), A050049 (1,2,3), A050053 (1,2,4), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3), A050069 (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)); end proc;
    seq(a(n), n = 1..50); # Petros Hadjicostas, Nov 11 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 2, 1}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 11 2019

A050045 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n 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, 4, 5, 9, 11, 13, 14, 27, 38, 47, 52, 56, 58, 60, 61, 121, 179, 235, 287, 334, 372, 399, 413, 426, 437, 446, 451, 455, 457, 459, 460, 919, 1376, 1831, 2282, 2728, 3165, 3591, 4004, 4403, 4775, 5109, 5396, 5631, 5810, 5931
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050037 (1,1,4), A050041 (1,2,1), A050049 (1,2,3), A050053 (1,2,4), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3), A050069 (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)):
    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[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 07 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 14 2019

A050053 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n 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) = 4.

Original entry on oeis.org

1, 2, 4, 6, 7, 13, 17, 19, 20, 39, 56, 69, 76, 82, 86, 88, 89, 177, 263, 345, 421, 490, 546, 585, 605, 624, 641, 654, 661, 667, 671, 673, 674, 1347, 2018, 2685, 3346, 4000, 4641, 5265, 5870, 6455, 7001, 7491, 7912, 8257, 8520, 8697
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050037 (1,1,4), A050041 (1,2,1), A050045 (1,2,2), A050049 (1,2,3), A050057 (1,3,1), A050061 (1,3,2), A050065 (1,3,3), A050069 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 2, 4][n], a(n - 1) + a(2^ceil(log[2](n - 1)) + 2 - n)); end proc;
    seq(a(n), n = 1 .. 48); # Petros Hadjicostas, Nov 09 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 2, 4}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 08 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 09 2019

A050057 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n 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, 4, 5, 9, 10, 13, 14, 27, 37, 46, 51, 55, 56, 59, 60, 119, 175, 230, 281, 327, 364, 391, 405, 418, 428, 437, 442, 446, 447, 450, 451, 901, 1348, 1794, 2236, 2673, 3101, 3519, 3924, 4315, 4679, 5006, 5287, 5517, 5692, 5811
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. similar sequences with different initial conditions: A050025 (1,1,1), A050029 (1,1,2), A050033 (1,1,3), A050037 (1,1,4), A050041 (1,2,1), A050045 (1,2,2), A050049 (1,2,3), A050053 (1,2,4), A050061 (1,3,2), A050065 (1,3,3), A050069 (1,3,4).

Programs

  • Maple
    a := proc(n) option remember;
    `if`(n < 4, [1, 3, 1][n], a(n - 1) + a(Bits:-Iff(n - 2, n - 2) + 3 - n)); end proc;
    seq(a(n), n = 1..48); # Petros Hadjicostas, Nov 08 2019
  • Mathematica
    Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 3, 1}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 08 2015 *)

Extensions

Name edited by Petros Hadjicostas, Nov 08 2019
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