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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A344264 When computing A229037, the value of the n-th term will add up to n-1 new constraints on the n-1 following terms; a(n) is the number of new constraints that the computation of A229037(n) brings.

Original entry on oeis.org

0, 1, 2, 2, 2, 5, 5, 7, 7, 4, 4, 8, 3, 3, 9, 9, 16, 15, 9, 11, 12, 15, 15, 23, 12, 14, 23, 8, 7, 16, 6, 6, 15, 14, 26, 21, 5, 6, 10, 4, 4, 12, 11, 27, 24, 13, 19, 18, 34, 31, 49, 24, 28, 47, 46, 22, 19, 21, 23, 48, 18, 18, 44, 20, 39, 57, 47, 40, 38, 43, 46
Offset: 1

Views

Author

Rémy Sigrist, May 13 2021

Keywords

Comments

Once A229037(n) has been computed, we have the following constraints:
- for k = 1..n-1, A229037(n + k) <> 2*A229037(n) - A229037(n - k),
- if 2*A229037(n) - A229037(n - k) <= 0, then we ignore this constraint,
- if 2*A229037(n) - A229037(n - k) = 2*A229037(n') - A229037(n' - k')
for some n' < n and k' < n' such that n + k = n' + k',
then we also ignore this constraint.

Examples

			The first terms, alongside the corresponding value of A229037 (denoted by f(n)) and the new constraints, are:
  n  a(n)  f(n)  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19
  -  ----  ----  -  -  -  -  -  -  -  -  -  --  --  --  --  --  --  --  --  --  --
  1     0     1  .  .  .  .  .  .  .  .  .  .   .   .   .   .   .   .   .   .   .
  2     1     1  .  .  1  .  .  .  .  .  .  .   .   .   .   .   .   .   .   .   .
  3     2     2  .  .  .  3  3  .  .  .  .  .   .   .   .   .   .   .   .   .   .
  4     2     1  .  .  .  .  .  1  1  .  .  .   .   .   .   .   .   .   .   .   .
  5     2     1  .  .  .  .  .  .  .  1  1  .   .   .   .   .   .   .   .   .   .
  6     5     2  .  .  .  .  .  .  3  3  2   3   3  .   .   .   .   .   .   .   .
  7     5     2  .  .  .  .  .  .  .  2  3  .    2   3   3  .   .   .   .   .   .
  8     7     4  .  .  .  .  .  .  .  .  6   6   7   7   6   7   7  .   .   .   .
  9     7     4  .  .  .  .  .  .  .  .  .   4   6   6   7  .    6   7   7  .   .
		

Crossrefs

Programs

  • PARI
    See Links section.

Formula

a(n) < n.

A344322 a(n) is the number of forbidden values when computing A229037(n).

Original entry on oeis.org

0, 0, 1, 1, 1, 1, 2, 3, 4, 3, 4, 4, 3, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 8, 7, 9, 9, 8, 9, 9, 9, 8, 9, 9, 8, 8, 8, 8, 7, 8, 6, 8, 9, 7, 8, 9, 7, 9, 8, 9, 9, 8, 9, 10, 10, 11, 10, 11, 11, 11, 11, 11, 11, 13, 15, 14, 14, 13, 15, 17, 16, 17, 15, 16, 17, 16, 16, 17
Offset: 1

Views

Author

Rémy Sigrist, May 15 2021

Keywords

Comments

In other words, a(n) is the number of distinct positive terms of the form 2*A229037(n - k) - A229037(n - 2*k) with n > 2*k > 0.

Examples

			For n=14, we have:
- 2*A229037(13) - A229037(12) = 2*1 - 2 = 0,
- 2*A229037(12) - A229037(10) = 2*2 - 1 = 3,
- 2*A229037(11) - A229037(8) = 2*1 - 4 = -2,
- 2*A229037(10) - A229037(6) = 2*1 - 2 = 0,
- 2*A229037(9) - A229037(4) = 2*4 - 1 = 7,
- 2*A229037(8) - A229037(2) = 2*4 - 1 = 7,
- so a(14) = #{3, 7} = 2.
		

Crossrefs

Programs

  • PARI
    \\ See Links section.
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