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 31-40 of 40 results.

A374394 Irregular table T(n, k), n >= 0, 0 <= k < A277561(1+A003754(n)), read by rows; the n-th row lists the numbers z <= n such that the Zeckendorf representations of z and n-z have no common Fibonacci numbers and when combined together correspond to the lazy Fibonacci representation of n.

Original entry on oeis.org

0, 0, 1, 0, 2, 1, 2, 0, 1, 3, 4, 2, 3, 2, 4, 0, 2, 5, 7, 1, 2, 6, 7, 3, 4, 5, 6, 3, 7, 4, 7, 0, 1, 3, 4, 8, 9, 11, 12, 2, 3, 10, 11, 2, 4, 10, 12, 5, 7, 8, 10, 6, 7, 9, 10, 5, 6, 11, 12, 7, 11, 7, 12, 0, 2, 5, 7, 13, 15, 18, 20, 1, 2, 6, 7, 14, 15, 19, 20, 3, 4, 5, 6, 16, 17, 18, 19
Offset: 0

Views

Author

Rémy Sigrist, Jul 07 2024

Keywords

Examples

			Triangle T(n, k) begins:
  n   n-th row
  --  ------------------------
   0  0
   1  0, 1
   2  0, 2
   3  1, 2
   4  0, 1, 3, 4
   5  2, 3
   6  2, 4
   7  0, 2, 5, 7
   8  1, 2, 6, 7
   9  3, 4, 5, 6
  10  3, 7
  11  4, 7
  12  0, 1, 3, 4, 8, 9, 11, 12
  13  2, 3, 10, 11
  14  2, 4, 10, 12
		

Crossrefs

Programs

  • PARI
    \\ See Links section.

Formula

T(n, k) = A022290(A374354(1+A003754(n)), k).

A374395 a(n) is the first term in the n-th row of A374394.

Original entry on oeis.org

0, 0, 0, 1, 0, 2, 2, 0, 1, 3, 3, 4, 0, 2, 2, 5, 6, 5, 7, 7, 0, 1, 3, 3, 4, 8, 10, 10, 8, 9, 11, 11, 12, 0, 2, 2, 5, 6, 5, 7, 7, 13, 14, 16, 16, 17, 13, 15, 15, 18, 19, 18, 20, 20, 0, 1, 3, 3, 4, 8, 10, 10, 8, 9, 11, 11, 12, 21, 23, 23, 26, 27, 26, 28, 28, 21
Offset: 0

Views

Author

Rémy Sigrist, Jul 10 2024

Keywords

Comments

a(n) is the least number z >= 0 such that the Zeckendorf representations of z and n-z have no common Fibonacci numbers and when combined together correspond to the lazy Fibonacci representation of n.

Crossrefs

Programs

  • PARI
    \\ See Links section.

Formula

a(n) = A022290(A374355(1+A003754(n)), k).
a(n) = n - A374396(n).

A374396 a(n) is the last term in the n-th row of A374394.

Original entry on oeis.org

0, 1, 2, 2, 4, 3, 4, 7, 7, 6, 7, 7, 12, 11, 12, 10, 10, 12, 11, 12, 20, 20, 19, 20, 20, 17, 16, 17, 20, 20, 19, 20, 20, 33, 32, 33, 31, 31, 33, 32, 33, 28, 28, 27, 28, 28, 33, 32, 33, 31, 31, 33, 32, 33, 54, 54, 53, 54, 54, 51, 50, 51, 54, 54, 53, 54, 54, 46
Offset: 0

Views

Author

Rémy Sigrist, Jul 10 2024

Keywords

Comments

a(n) is the greatest number z <= n such that the Zeckendorf representations of z and n-z have no common Fibonacci numbers and when combined together correspond to the lazy Fibonacci representation of n.

Crossrefs

Programs

  • PARI
    \\ See Links section.

Formula

a(n) = A022290(A374356(1+A003754(n)), k).
a(n) = n - A374395(n).

A382113 Gray code transformation of the Zeckendorf representation of n.

Original entry on oeis.org

0, 1, 3, 6, 5, 11, 10, 8, 19, 18, 16, 13, 14, 32, 31, 29, 26, 27, 21, 22, 24, 53, 52, 50, 47, 48, 42, 43, 45, 34, 35, 37, 40, 39, 87, 86, 84, 81, 82, 76, 77, 79, 68, 69, 71, 74, 73, 55, 56, 58, 61, 60, 66, 65, 63, 142, 141, 139, 136, 137, 131, 132, 134, 123, 124
Offset: 0

Views

Author

Jeffrey Shallit, Mar 16 2025

Keywords

Examples

			For n = 5: its Zeckendorf representation is 1000; the Gray code equivalent is 1111, which evaluates to 1+2+3+5=11. So a(5) = 11.
		

Crossrefs

Cf. A382116 (terms sorted).

Formula

a(n) = A022290(A006068(A003714(n))). In other words, take n, calculate its Zeckendorf representation, find the Gray code equivalent of that binary string; then regard it as the Zeckendorf representation of a number (even though it might have two consecutive 1's).

A356875 Square array, n >= 0, k >= 0, read by descending antidiagonals. A(n,k) = A022341(n)*2^k.

Original entry on oeis.org

1, 2, 5, 4, 10, 9, 8, 20, 18, 17, 16, 40, 36, 34, 21, 32, 80, 72, 68, 42, 33, 64, 160, 144, 136, 84, 66, 37, 128, 320, 288, 272, 168, 132, 74, 41, 256, 640, 576, 544, 336, 264, 148, 82, 65, 512, 1280, 1152, 1088, 672, 528, 296, 164, 130, 69, 1024, 2560, 2304, 2176, 1344, 1056, 592, 328, 260, 138, 73
Offset: 0

Views

Author

Peter Munn, Sep 02 2022

Keywords

Comments

The nonzero Fibbinary numbers (A003714) arranged in rows where each successive term is twice the preceding term; a (transposed) Fibbinary equivalent of A054582.
Write the first term in each row as Sum_{i in S} 2^i, where S is a set of nonnegative integers, then n = Sum_{i in S} F_i, where F_i is the i-th Fibonacci number, A000045(i).
More generally, if the terms are represented in binary, and the binary weighting of the digits (2^0, 2^1, 2^2, ...) is replaced with Fibonacci weighting (F_0, F_1, F_2, ...), we get the extended Wythoff array (A287870). If the weighting of the Zeckendorf representation is used (F_2, F_3, F_4, ...), we get the (unextended) Wythoff array (A035513).

Examples

			Square array A(n,k) begins:
   1    2    4    8    16    32    64   128 ...
   5   10   20   40    80   160   320   640 ...
   9   18   36   72   144   288   576  1152 ...
  17   34   68  136   272   544  1088  2176 ...
  21   42   84  168   336   672  1344  2688 ...
  33   66  132  264   528  1056  2112  4224 ...
  37   74  148  296   592  1184  2368  4736 ...
  41   82  164  328   656  1312  2624  5248 ...
  65  130  260  520  1040  2080  4160  8320 ...
  69  138  276  552  1104  2208  4416  8832 ...
  ...
The defining characteristic of a Fibbinary number is that its binary representation does not have a 1 followed by another 1. Shown in binary the array begins:
      1      10      100      1000 ...
    101    1010    10100    101000 ...
   1001   10010   100100   1001000 ...
  10001  100010  1000100  10001000 ...
  10101  101010  1010100  10101000 ...
  ...
		

Crossrefs

See the comments for the relationship to: A000045, A003714, A035513, A054582, A287870.
See the formula section for the relationship to: A022290, A022341, A356874.

Formula

A(n,0) = A022341(n), otherwise A(n,k) = 2*A(n,k-1).
A287870(n+1,k+1) = A356874(floor(A(n,k)/2)).
A035513(n+1,k+1) = A022290(A(n,k)).

A356969 A(n, k) is the sum of the terms in common in the dual Zeckendorf representations of n and of k; square array A(n, k) read by antidiagonals, n, k >= 0.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 0, 0, 3, 0, 0, 0, 0, 1, 2, 1, 1, 2, 1, 0, 0, 0, 2, 2, 4, 2, 2, 0, 0, 0, 1, 2, 3, 3, 3, 3, 2, 1, 0, 0, 1, 2, 2, 4, 5, 4, 2, 2, 1, 0, 0, 0, 0, 3, 0, 5, 5, 0, 3, 0, 0, 0, 0, 1, 2, 1, 1, 2, 6, 2, 1, 1, 2, 1, 0
Offset: 0

Views

Author

Rémy Sigrist, Sep 06 2022

Keywords

Comments

The dual Zeckendorf representation corresponds to the lazy Fibonacci representation.
See A334348 for the sequence dealing with Zeckendorf (or greedy Fibonacci) representations. Unlike A334348, the present sequence is not associative.

Examples

			Square array A(n, k) begins:
  n\k|  0  1  2  3  4  5  6  7  8  9  10  11  12  13
  ---+----------------------------------------------
    0|  0  0  0  0  0  0  0  0  0  0   0   0   0   0
    1|  0  1  0  1  1  0  1  0  1  1   0   1   1   0
    2|  0  0  2  2  0  2  2  2  2  0   2   2   0   2
    3|  0  1  2  3  1  2  3  2  3  1   2   3   1   2
    4|  0  1  0  1  4  3  4  0  1  4   3   4   4   3
    5|  0  0  2  2  3  5  5  2  2  3   5   5   3   5
    6|  0  1  2  3  4  5  6  2  3  4   5   6   4   5
    7|  0  0  2  2  0  2  2  7  7  5   7   7   0   2
    8|  0  1  2  3  1  2  3  7  8  6   7   8   1   2
    9|  0  1  0  1  4  3  4  5  6  9   8   9   4   3
   10|  0  0  2  2  3  5  5  7  7  8  10  10   3   5
   11|  0  1  2  3  4  5  6  7  8  9  10  11   4   5
   12|  0  1  0  1  4  3  4  0  1  4   3   4  12  11
   13|  0  0  2  2  3  5  5  2  2  3   5   5  11  13
		

Crossrefs

Programs

  • PARI
    See Links section.

Formula

A(n, k) = A022290(A003754(n+1) AND A003754(k+1)) (where AND denotes the bitwise AND operator, A004198).
A(n, k) = A(k, n).
A(n, 0) = 0.
A(n, n) = n.

A197432 a(n) = Sum_{k>=0} A030308(n,k)*C(k) where C(k) is the k-th Catalan number (A000108).

Original entry on oeis.org

0, 1, 1, 2, 2, 3, 3, 4, 5, 6, 6, 7, 7, 8, 8, 9, 14, 15, 15, 16, 16, 17, 17, 18, 19, 20, 20, 21, 21, 22, 22, 23, 42, 43, 43, 44, 44, 45, 45, 46, 47, 48, 48, 49, 49, 50, 50, 51, 56, 57, 57, 58, 58, 59, 59, 60, 61, 62, 62, 63, 63, 64, 64, 65
Offset: 0

Views

Author

Philippe Deléham, Oct 15 2011

Keywords

Comments

Replace 2^k with A000108(k) in binary expansion of n.

Examples

			11 = 1011_2, so a(11) = 1*1 + 1*1 + 0*2 + 1*5 = 7.
		

Crossrefs

Other sequences that are built by replacing 2^k in binary representation with other numbers: A022290 (Fibonacci), A029931 (natural numbers), A059590 (factorials), A089625 (primes), A197354 (odd numbers).

Formula

G.f.: (1/(1 - x))*Sum_{k>=0} Catalan number(k)*x^(2^k)/(1 + x^(2^k)). - Ilya Gutkovskiy, Jul 23 2017

A309840 If n = Sum (2^e_k) then a(n) = Product (Fibonacci(e_k + 3)).

Original entry on oeis.org

1, 2, 3, 6, 5, 10, 15, 30, 8, 16, 24, 48, 40, 80, 120, 240, 13, 26, 39, 78, 65, 130, 195, 390, 104, 208, 312, 624, 520, 1040, 1560, 3120, 21, 42, 63, 126, 105, 210, 315, 630, 168, 336, 504, 1008, 840, 1680, 2520, 5040, 273, 546, 819, 1638, 1365, 2730, 4095, 8190
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 19 2019

Keywords

Examples

			23 = 2^0 + 2^1 + 2^2 + 2^4 so a(23) = Fibonacci(3) * Fibonacci(4) * Fibonacci(5) * Fibonacci(7) = 390.
		

Crossrefs

Programs

  • Mathematica
    nmax = 55; CoefficientList[Series[Product[(1 + Fibonacci[k + 3] x^(2^k)), {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x]
    a[0] = 1; a[n_] := Fibonacci[Floor[Log[2, n]] + 3] a[n - 2^Floor[Log[2, n]]]; Table[a[n], {n, 0, 55}]
  • PARI
    a(n)={vecprod([fibonacci(k+2) | k<-Vec(select(b->b, Vecrev(digits(n, 2)), 1))])} \\ Andrew Howroyd, Aug 19 2019

Formula

G.f.: Product_{k>=0} (1 + Fibonacci(k + 3) * x^(2^k)).
a(0) = 1; a(n) = Fibonacci(floor(log_2(n)) + 3) * a(n - 2^floor(log_2(n))).
a(2^(k-2)-1) = A003266(k).

A326032 a(2^x + ... + 2^z) = w(x) + ... + w(z), where x...z are distinct nonnegative integers and w = A000120.

Original entry on oeis.org

0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 3, 3, 4, 4, 4, 4, 5
Offset: 0

Views

Author

Gus Wiseman, Jul 22 2019

Keywords

Comments

From Robert Israel, Jul 23 2019: (Start)
a(2*n+1)=a(2*n).
a(n)=1 if and only if n > 1 is in A283526. (End)

Examples

			For example, a(6) = a(2^2 + 2^1) = w(2) + w(1) = 2.
		

Crossrefs

Other sequences that are built by replacing 2^k in the binary representation with other numbers: A022290 (Fibonacci), A059590 (factorials), A073642, A089625 (primes), A116549, A326031.

Programs

  • Maple
    Bwt:= proc(n) option remember; convert(convert(n,base,2),`+`) end proc:
    f:= proc(n) local L,i;
      L:= convert(n,base,2);
      add(L[i]*Bwt(i-1),i=1..nops(L))
    end proc:
    map(f, [$0..100]); # Robert Israel, Jul 23 2019
  • Mathematica
    bpe[n_]:=Join@@Position[Reverse[IntegerDigits[n,2]],1];
    Table[Total[Length/@bpe/@(bpe[n]-1)],{n,0,100}]

A361789 A(n, k) is the sum of the distinct terms in the dual Zeckendorf representations of n or of k; square array A(n, k) read by antidiagonals, n, k >= 0.

Original entry on oeis.org

0, 1, 1, 2, 1, 2, 3, 3, 3, 3, 4, 3, 2, 3, 4, 5, 4, 3, 3, 4, 5, 6, 6, 6, 3, 6, 6, 6, 7, 6, 5, 6, 6, 5, 6, 7, 8, 8, 6, 6, 4, 6, 6, 8, 8, 9, 8, 7, 6, 6, 6, 6, 7, 8, 9, 10, 9, 8, 8, 6, 5, 6, 8, 8, 9, 10, 11, 11, 11, 8, 11, 6, 6, 11, 8, 11, 11, 11, 12, 11, 10, 11, 11, 10, 6, 10, 11, 11, 10, 11, 12
Offset: 0

Views

Author

Rémy Sigrist, Mar 24 2023

Keywords

Comments

The dual Zeckendorf representation corresponds to the lazy Fibonacci representation (see A356771 for further details).

Examples

			Array A(n, k) begins:
  n\k |  0   1   2   3   4   5   6   7   8   9  10  11  12  13
  ----+-------------------------------------------------------
    0 |  0   1   2   3   4   5   6   7   8   9  10  11  12  13
    1 |  1   1   3   3   4   6   6   8   8   9  11  11  12  14
    2 |  2   3   2   3   6   5   6   7   8  11  10  11  14  13
    3 |  3   3   3   3   6   6   6   8   8  11  11  11  14  14
    4 |  4   4   6   6   4   6   6  11  11   9  11  11  12  14
    5 |  5   6   5   6   6   5   6  10  11  11  10  11  14  13
    6 |  6   6   6   6   6   6   6  11  11  11  11  11  14  14
    7 |  7   8   7   8  11  10  11   7   8  11  10  11  19  18
    8 |  8   8   8   8  11  11  11   8   8  11  11  11  19  19
    9 |  9   9  11  11   9  11  11  11  11   9  11  11  17  19
   10 | 10  11  10  11  11  10  11  10  11  11  10  11  19  18
   11 | 11  11  11  11  11  11  11  11  11  11  11  11  19  19
   12 | 12  12  14  14  12  14  14  19  19  17  19  19  12  14
   13 | 13  14  13  14  14  13  14  18  19  19  18  19  14  13
		

Crossrefs

Programs

  • PARI
    See Links section.

Formula

A(n, k) = A022290(A003754(n+1) OR A003754(k+1)) (where OR denotes the bitwise OR operator, A004198).
A(n, k) = A(k, n).
A(n, 0) = n.
A(n, n) = n.
A(A(m, n), k) = A(m, A(n, k)).
A(A(n, k), n) = A(n, k).
A(n, A361756(n, k)) = n.
Previous Showing 31-40 of 40 results.