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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A095089 Fib101 primes, i.e., primes p whose Zeckendorf-expansion A014417(p) ends as one, zero, one.

Original entry on oeis.org

17, 59, 67, 101, 127, 211, 271, 313, 347, 373, 389, 449, 457, 491, 499, 593, 601, 643, 661, 677, 787, 821, 881, 983, 991, 1033, 1093, 1109, 1237, 1279, 1321, 1381, 1423, 1499, 1559, 1567, 1601, 1609, 1669, 1753, 1787, 1847, 1889, 1931, 1999
Offset: 1

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Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Intersection of A000040 and A134860. Cf. A014417, A095069.

Programs

  • 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))[-3:]=="101"
    print([n for n in primerange(1, 2001) if ok(n)]) # Indranil Ghosh, Jun 08 2017

A187951 Positions of 0 in A187950; complement of A187952.

Original entry on oeis.org

2, 4, 5, 7, 10, 12, 13, 15, 17, 18, 20, 23, 25, 26, 28, 31, 33, 34, 36, 38, 39, 41, 44, 46, 47, 49, 51, 52, 54, 57, 59, 60, 62, 65, 67, 68, 70, 72, 73, 75, 78, 80, 81, 83, 86, 88, 89, 91, 93, 94, 96, 99, 101, 102, 104, 106, 107, 109, 112, 114, 115, 117, 120, 122, 123, 125, 127, 128, 130, 133, 135, 136, 138, 140, 141, 143, 146, 148, 149, 151, 154
Offset: 1

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Author

Clark Kimberling, Mar 16 2011

Keywords

Comments

See A187950.
Union of the Wythoff AAB-numbers A134860, the Wythoff BA-numbers A035336 and the Wythoff BB-numbers A101864. - Michel Dekking, Sep 14 2016

Crossrefs

Programs

A276757 Infinite Fibonacci word on the alphabet {1,2,3,4,5}.

Original entry on oeis.org

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

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Author

Michel Dekking, Sep 17 2016

Keywords

Comments

Start with the infinite Fibonacci word A003849, which is 0100101001001010010... and replace each 0 by 1,2,3 and each 1 by 4,5.
The unique fixed point of the 4-block Fibonacci substitution 1 -> 12, 2 -> 3, 3 -> 45, 4 -> 12, 5 -> 3. Here the 4-blocks are coded as 0100 <-> 1, 1001 <-> 2, 0010 <-> 3, 0101 <-> 4, 1010 <-> 5.

Crossrefs

Formula

Let A(n) = floor(n*phi), B(n) = n + floor(n*phi), i.e., A and B are the lower and upper Wythoff sequences, A = A000201, B = A001950. Then a(n) = 1 if n = A(A(A(k))) for some k; a(n) = 2 if n = B(A(k)) for some k; a(n) = 3 if n = A(B(k)) for some k; a(n) = 4 if n = A(A(B(k))) for some k; a(n) = 5 if n = B(B(k)) for some k.

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

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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.