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.

Previous Showing 11-17 of 17 results.

A373228 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 8; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 8.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 6, 9, 10, 11, 9, 12, 13, 14, 12, 15, 16, 17, 15, 18, 19, 17, 21, 18, 21, 23, 24, 19, 26, 23, 28, 24, 28, 27, 24, 31, 32, 28, 24, 36, 36, 33, 23, 37, 38, 40, 27, 39, 38, 42, 35, 41, 38, 43, 42, 44, 39, 44, 42, 51, 42, 45, 48, 47, 51, 44, 54, 48, 52, 49, 53
Offset: 1

Views

Author

Nathan Fox, May 28 2024

Keywords

Comments

Similar to A278055 but with different starting values.
Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
a(n) exists for n <= 3*10^7.

Crossrefs

Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

  • Mathematica
    a[n_] := a[n] = If[0 < n < 9, n, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]];
    Array[a, 100] (* Paolo Xausa, May 31 2024 *)

A373229 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 9; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 9.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 6, 10, 11, 12, 9, 13, 14, 15, 12, 16, 17, 18, 15, 19, 20, 17, 22, 18, 22, 24, 25, 22, 21, 29, 28, 22, 24, 34, 27, 29, 28, 32, 27, 37, 33, 31, 34, 35, 36, 34, 36, 41, 36, 41, 36, 41, 43, 41, 43, 40, 48, 42, 41, 46, 46, 52, 43, 51, 46, 53, 51, 46, 56, 48
Offset: 1

Views

Author

Nathan Fox, May 28 2024

Keywords

Comments

Similar to A278055 but with different starting values.
Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
a(n) exists for n <= 3*10^7.

Crossrefs

Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

  • Mathematica
    a[n_] := a[n] = If[0 < n < 10, n, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]];
    Array[a, 100] (* Paolo Xausa, May 31 2024 *)

A373230 Relative of Hofstadter Q-sequence: a(n) = 0 for n <= 0, a(n) = n for 1 <= n <= 10; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 10.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 6, 11, 12, 13, 9, 14, 15, 16, 12, 17, 18, 19, 15, 20, 21, 17, 23, 18, 23, 25, 26, 22, 21, 31, 29, 21, 28, 34, 27, 29, 31, 27, 38, 33, 34, 31, 39, 37, 37, 30, 44, 36, 39, 35, 43, 45, 43, 30, 50, 50, 38, 42, 51, 48, 43, 40, 55, 51, 52, 37, 60, 57, 47
Offset: 1

Views

Author

Nathan Fox, May 28 2024

Keywords

Comments

Similar to A278055 but with different starting values.
a(1015) = 1036. This is the smallest index for which a(n) > n. So, without the condition that a(n) = 0 for n <= 0, this sequence would be finite and have exactly 1015 terms.
Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
a(n) exists for n <= 3*10^7.

Crossrefs

Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

  • Mathematica
    a[n_] := a[n] = Which[n < 1, 0, n < 11, n, True, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]]; Array[a, 100] (* Paolo Xausa, May 31 2024 *)

A373231 Relative of Hofstadter Q-sequence: a(n) = 0 for n <= 0, a(n) = n for 1 <= n <= 11; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 11.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 6, 12, 13, 14, 9, 15, 16, 17, 12, 18, 19, 20, 15, 21, 22, 17, 24, 18, 24, 26, 27, 22, 21, 33, 30, 20, 29, 36, 27, 24, 36, 33, 31, 28, 42, 31, 33, 32, 48, 36, 25, 44, 44, 46, 22, 56, 38, 41, 40, 50, 43, 44, 43, 56, 49, 42, 45, 44, 67, 43, 47, 52
Offset: 1

Views

Author

Nathan Fox, May 28 2024

Keywords

Comments

Similar to A278055 but with different starting values.
a(117) = 120. This is the smallest index for which a(n) > n. So, without the condition that a(n) = 0 for n <= 0, this sequence would be finite and have exactly 117 terms.
Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
a(n) exists for n <= 3*10^7.

Crossrefs

Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

  • Mathematica
    a[n_] := a[n] = Which[n < 1, 0, n < 12, n, True, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]]; Array[a, 100] (* Paolo Xausa, May 31 2024 *)

A373232 Relative of Hofstadter Q-sequence: a(n) = 0 for n <= 0, a(n) = n for 1 <= n <= 12; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 12.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 6, 13, 14, 15, 9, 16, 17, 18, 12, 19, 20, 21, 15, 22, 23, 17, 25, 18, 25, 27, 28, 22, 21, 35, 31, 19, 30, 31, 40, 25, 31, 27, 47, 31, 33, 24, 46, 35, 43, 24, 51, 32, 49, 33, 44, 37, 55, 40, 39, 46, 50, 44, 43, 54, 47, 40, 58, 50, 43, 57, 53
Offset: 1

Views

Author

Nathan Fox, May 28 2024

Keywords

Comments

Similar to A278055 but with different starting values.
a(45) = 47. This is the smallest index for which a(n) > n. So, without the condition that a(n) = 0 for n <= 0, this sequence would be finite and have exactly 45 terms.
Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
a(n) exists for n <= 3*10^7.

Crossrefs

Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

  • Mathematica
    a[n_] := a[n] = Which[n < 1, 0, n < 13, n, True, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]]; Array[a, 100] (* Paolo Xausa, May 31 2024 *)

A373233 Relative of Hofstadter Q-sequence: a(n) = 0 for n <= 0, a(n) = n for 1 <= n <= 13; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 13.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 6, 14, 15, 16, 9, 17, 18, 19, 12, 20, 21, 22, 15, 23, 24, 17, 26, 18, 26, 28, 29, 22, 21, 37, 32, 18, 23, 38, 42, 24, 26, 39, 37, 37, 31, 33, 46, 32, 41, 38, 40, 36, 42, 49, 36, 46, 38, 56, 42, 48, 35, 62, 31, 52, 58, 59, 32, 43, 53, 82
Offset: 1

Views

Author

Nathan Fox, May 28 2024

Keywords

Comments

Similar to A278055 but with different starting values.
a(73) = 82. This is the smallest index for which a(n) > n. So, without the condition that a(n) = 0 for n <= 0, this sequence would be finite and have exactly 73 terms.
Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
a(n) exists for n <= 3*10^7.

Crossrefs

Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

  • Mathematica
    a[n_] := a[n] = Which[n < 1, 0, n < 14, n, True, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]]; Array[a, 100] (* Paolo Xausa, May 31 2024 *)

A274055 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 42; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 42.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 3, 43, 44, 5, 45, 6, 7, 46, 48, 10, 8, 48, 52, 12, 49, 14, 54, 11, 53, 57, 16, 13, 17, 15, 56, 20, 20
Offset: 1

Views

Author

Nathan Fox, Nov 13 2016

Keywords

Comments

In calculating terms of this sequence, use the convention that a(n)=0 for n<=0.
This sequence eventually settles into a pattern resembling A272610.

Crossrefs

Formula

If the index is between 77 and 89 (inclusive), then a(5n) = 3, a(5n+1) = 5, a(5n+2) = 88n-1188, a(5n+3) = 5, a(5n+4) = 88.
If the index is between 95 and 397 (inclusive), then a(5n) = 396n-6820, a(5n+1) = 3, a(5n+2) = 396, a(5n+3) = 3, a(5n+4) = 5.
If the index is between 403 and 24860 (inclusive), then a(5n) = 24860, a(5n+1) = 3, a(5n+2) = 5, a(5n+3) = 24860n-1939476, a(5n+4) = 5.
If the index is at least 24863, then a(5n) = 24860*A272613(n-4972), a(5n+1) = 4, a(5n+2) = 5*A272611(n-4972), a(5n+3) = 5*A272611(n-4971), a(5n+4) = 5*A272612(n-4971). This pattern lasts as long as A272611 exists (which is conjectured to be forever).
Previous Showing 11-17 of 17 results.