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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A095082 Fib00 primes, i.e., primes p whose Zeckendorf-expansion A014417(p) ends with two zeros.

Original entry on oeis.org

3, 5, 11, 13, 29, 37, 47, 71, 73, 79, 89, 97, 107, 113, 131, 139, 149, 157, 173, 181, 191, 199, 223, 233, 241, 251, 257, 283, 293, 317, 359, 367, 401, 409, 419, 443, 461, 479, 487, 503, 521, 547, 563, 571, 587, 613, 631, 647, 673, 683, 691, 733
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Cf. A095062. Intersection of A000040 and A026274. Union of A095085 and A095088.

Programs

  • PARI
    list(lim)=my(v=List(), w=quadgen(20), phi=(1+w)/2, p2=phi^2, x=(2*phi-2)*p2, q);  lim=lim\1+1; while(xCharles R Greathouse IV, Nov 10 2021
  • Python
    from sympy import fibonacci, primerange
    def a(n):
        k=0
        x=0
        while n>0:
            k=0
            while fibonacci(k)<=n: k+=1
            x+=10**(k - 3)
            n-=fibonacci(k - 1)
        return x
    def ok(n): return str(a(n))[-2:]=="00"
    print([n for n in primerange(1, 1001) if ok(n)]) # Indranil Ghosh, Jun 08 2017
    

A332502 Rectangular array read by antidiagonals: T(n,k) = floor(n + k*r), where r = golden ratio = (1+sqrt(5))/2.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, May 08 2020

Keywords

Comments

Every nonnegative integer occurs exactly once in the union of row 0 and the main diagonal.
Column 0: Nonnegative integers, A001477.
Row 0: Lower Wythoff sequence, A000201.
Row 1: A026351.
Row 2: A026355 (and essentially A099267).
Main Diagonal: Upper Wythoff sequence, A001950.
Diagonal (1,4,6,9,...) = A003622;
Diagonal (3,5,8,11,...) = A026274;
Diagonal (1,3,6,8,...) = A026352;
Diagonal (2,4,7,9,...) = A026356.

Examples

			Northwest corner:
  0   1   3   4   6   8    9    11   12   14   16
  1   2   4   5   7   9    10   12   13   15   17
  2   3   5   6   8   10   11   13   14   16   18
  3   4   6   7   9   11   12   14   15   17   19
  4   5   7   8   10  12   13   15   16   18   20
  5   6   8   9   11  13   14   16   17   19   21
As a triangle (antidiagonals):
  0
  1   1
  2   2   3
  3   3   4   4
  4   4   5   5   6
  5   5   6   6   7   8
  6   6   7   7   8   9   9
		

Crossrefs

Programs

  • Mathematica
    t[n_, k_] := Floor[n + k*GoldenRatio];
    Grid[Table[t[n, k], {n, 0, 10}, {k, 0, 10}]] (* array *)
    u = Table[t[n - k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten  (* sequence *)

Formula

T(n,k) = floor(n + k*r), where r = golden ratio = (1+sqrt(5))/2.

A357316 A distension of the Wythoff array by inclusion of intermediate rows. Square array A(n,k), n >= 0, k >= 0, read by descending antidiagonals. If S is the set such that Sum_{i in S} F_i is the Zeckendorf representation of n then A(n,k) = Sum_{i in S} F_{i+k-2}.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 2, 2, 2, 1, 0, 3, 3, 3, 3, 2, 0, 5, 5, 5, 4, 3, 2, 0, 8, 8, 8, 7, 5, 4, 3, 0, 13, 13, 13, 11, 8, 6, 4, 3, 0, 21, 21, 21, 18, 13, 10, 7, 5, 3, 0, 34, 34, 34, 29, 21, 16, 11, 8, 6, 4, 0, 55, 55, 55, 47, 34, 26, 18, 13, 9, 6, 4
Offset: 0

Views

Author

Peter Munn, Sep 23 2022

Keywords

Comments

Note the Zeckendorf representation of 0 is taken to be the empty sum.
The Wythoff array A035513 is the subtable formed by rows 3, 11, 16, 24, 32, ... (A035337). If, instead, we use rows 2, 7, 10, 15, 20, ... (A035336) or 1, 4, 6, 9, 12, ... (A003622), we get the Wythoff array extended by 1 column (A287869) or 2 columns (A287870) respectively.
Similarly, using A035338 truncates by 1 column; and in general if S_k is column k of the Wythoff array then the rows here numbered by S_k form an array A_k that starts with column k-2 of the Wythoff array. (A_0 and A_1 are the 2 extended arrays mentioned above.) As every positive integer occurs exactly once in the Wythoff array, every row except row 0 of A(.,.) is a row of exactly one such A_k.
Columns 4 onwards match certain columns of the multiplication table for Knuth's Fibonacci (or circle) product (extended variant - see A135090 and formula below).
For k > 0, the first row to contain k is A348853(k).

Examples

			Example for n = 4, k = 3. The Zeckendorf representation of 4 is F_4 + F_2 = 3 + 1. So the values of i in the sums in the definition are 4 and 2; hence A(4,3) = Sum_{i = 2,4} F_{i+k-2} = F_{4+3-2} + F_{2+3-2} = F_5 + F_3 = 5 + 2 = 7.
Square array A(n,k) begins:
   n\k| 0   1    2    3    4    5    6
  ----+--------------------------------
   0  | 0   0    0    0    0    0    0  ...
   1* | 0   1    1    2    3    5    8  ...
   2  | 1   1    2    3    5    8   13  ...
   3  | 1   2    3    5    8   13   21  ...
   4* | 1   3    4    7   11   18   29  ...
   5  | 2   3    5    8   13   21   34  ...
   6* | 2   4    6   10   16   26   42  ...
   7  | 3   4    7   11   18   29   47  ...
   8  | 3   5    8   13   21   34   55  ...
   9* | 3   6    9   15   24   39   63  ...
  10  | 4   6   10   16   26   42   68  ...
  11  | 4   7   11   18   29   47   76  ...
  12* | 4   8   12   20   32   52   84  ...
  ...
The asterisked rows form the start of the extended Wythoff array (A287870).
		

Crossrefs

Columns, some differing initially: A005206 (1), A022342 (3), A026274 (4), A101345 (5), A101642 (6).
Rows: A000045 (1), A000204 (4).
Related to subtable A287870 as A130128 (as a square) is to A054582.
Other subtables: A035513, A287869.
See the comments for the relationship to A003622, A035336, A035337, A035338, A348853.
See the formula section for the relationship to A003714, A022342, A135090, A356874.

Programs

  • PARI
    A5206(m) = if(m>0,m-A5206(A5206(m-1)),0)
    A(n,k) = if(k==2,n, if(k==1,A5206(n), if(k==0,n-A5206(n), A(n,k-2)+A(n,k-1)))) \\ simple encoding of formulas, not efficient

Formula

For n >= 0, k >= 0 unless stated otherwise:
A(n,k) = A356874(floor(A003714(n)*2^(k-1))).
A(n,1) = A005206(n).
A(n,2) = n.
A(n,k+2) = A(n,k) + A(n,k+1).
A(A022342(n+1),k) = A(n,k+1).
For k >= 4, A(n,k) = A135090(n,A000045(k-2)).

A372302 Numbers k for which the Zeckendorf representation A014417(k) ends with "1001".

Original entry on oeis.org

6, 19, 27, 40, 53, 61, 74, 82, 95, 108, 116, 129, 142, 150, 163, 171, 184, 197, 205, 218, 226, 239, 252, 260, 273, 286, 294, 307, 315, 328, 341, 349, 362, 375, 383, 396, 404, 417, 430, 438, 451, 459, 472, 485, 493, 506, 519, 527, 540, 548, 561, 574, 582, 595, 603
Offset: 1

Views

Author

A.H.M. Smeets, Apr 25 2024

Keywords

Crossrefs

Tree of Zeckendorf subsequences of positive integers partitioned by their suffix part S (except initial term or offset in some cases). $ is the empty string. length(S) =
0 1 2 3 4 5 6 7
----------------------------------------------------------------------
$: 0: 00: 000: 0000: 00000: 000000:
100000: 0100000:
A035340 <------
10000:
1000: 01000:
A035338 <------
10: 010: 0010:
A035336 <------ A134861
1010: 01010:
A134863 <------
100: 0100:
A035337 <------
1: 01: 001: 0001:
1001: 01001:
A372302 <------
101: 0101:
A134860 <------
Suffixes 10^n, where ^ means n times repeated concatenation, are the (n+1)-th columns in the Wythoff array A083412 and A035513 (n >= 0).

Formula

Equals {A134859}\{A151915}.
a(n) = A134863(n) - 1 = A035338(n) + 1.
a(n) = a(n-1) + 8 + 5*A005614(n-2) = a(n-1) + F(6) + F(5)*A005614(n-2), n > 1, where F(k) is the k-th Fibonacci number (A000045).
Previous Showing 11-14 of 14 results.