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.

A327991 The complementary Fibonacci codes. Irregular triangle T(n, k) with n >= 0 and 0 <= k < A000045(n+1).

Original entry on oeis.org

1, 2, 2, 6, 2, 6, 30, 2, 6, 30, 10, 210, 2, 6, 30, 10, 210, 42, 70, 2310, 2, 6, 30, 10, 210, 42, 70, 2310, 14, 330, 462, 770, 30030, 2, 6, 30, 10, 210, 42, 70, 2310, 14, 330, 462, 770, 30030, 66, 110, 2730, 154, 4290, 6006, 10010, 510510
Offset: 0

Views

Author

Peter Luschny, Oct 09 2019

Keywords

Comments

The complementary Fibonacci codes are binary strings enumerated in an irregular triangle CF(n, k). The first few are shown below in the Example section. The complementary Fibonacci codes are the bitwise complements of the Fibonacci codes described in A327990, in ascending order.
The complementary Fibonacci codes are represented here through
T(n, k) = Product_{j=0..m} p(j)^c(j),
where p(j) is the j-th prime number, c = CF(n, k) and m = length(CF(n, k)).

Examples

			The complementary Fibonacci codes start:
[0] [[]]
[1] [[1]]
[2] [[1][11]]
[3] [[1][11][111]]
[4] [[1][11][111][101][1111]]
[5] [[1][11][111][101][1111][1101][1011][11111]]
[6] [[1][11][111][101][1111][1101][1011][11111][1001][11101][11011][10111][111111]]
[7] [[1][11][111][101][1111][1101][1011][11111][1001][11101][11011][10111][111111] [11001][10101][111101][10011][111011][110111][101111][1111111]]
The representation of the complementary Fibonacci codes starts:
[0] [1]
[1] [2]
[2] [2, 6]
[3] [2, 6, 30]
[4] [2, 6, 30, 10, 210]
[5] [2, 6, 30, 10, 210, 42, 70, 2310]
[6] [2, 6, 30, 10, 210, 42, 70, 2310, 14, 330, 462, 770, 30030]
[7] [2, 6, 30, 10, 210, 42, 70, 2310, 14, 330, 462, 770, 30030, 66, 110, 2730, 154, 4290, 6006, 10010, 510510]
		

Crossrefs

The diagonal is A002110 (primorial numbers).

Programs

  • SageMath
    @cached_function
    def FibonacciCodes(n):
        if n == 0 : return [[]]
        if n == 1 : return [[1]]
        A = [c.conjugate() for c in Compositions(n) if not(1 in c)]
        return FibonacciCodes(n-1) + [[2-i for i in a] for a in A]
    def A327991row(n):
        P = Primes()
        M = lambda C: mul(P[i]^c for (i, c) in enumerate(C))
        return [M(c) for c in FibonacciCodes(n)]
    for n in (0..7): print(A327991row(n))