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.

Showing 1-2 of 2 results.

A382130 Fractalization of the golden ratio.

Original entry on oeis.org

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

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Author

David Cleaver, Mar 16 2025

Keywords

Comments

Self-descriptive sequence: even indexed terms are the sequence itself, odd indexed terms are the decimal digits of the golden ratio.
This is an r1k1 fractal sequence, where r1k1 means: remove 1 term, keep 1 term, repeat. The Removed terms are the sequence that has been fractalized, and the Kept terms are the original fractal sequence.
This fractal sequence is not a Kimberling fractal sequence because if you delete the first occurrence of each term, the remaining sequence is not the same as the original.

Crossrefs

Bisection gives A001622 (odd part).

Formula

a(2n) = a(n); a(2n-1) = A001622(n), n >= 1.
a(n) = A001622(A003602(n)).

A382129 Fractalization of the prime numbers.

Original entry on oeis.org

2, 2, 3, 2, 5, 3, 7, 2, 11, 5, 13, 3, 17, 7, 19, 2, 23, 11, 29, 5, 31, 13, 37, 3, 41, 17, 43, 7, 47, 19, 53, 2, 59, 23, 61, 11, 67, 29, 71, 5, 73, 31, 79, 13, 83, 37, 89, 3, 97, 41, 101, 17, 103, 43, 107, 7, 109, 47, 113, 19, 127, 53, 131, 2, 137, 59, 139, 23, 149, 61, 151, 11, 157
Offset: 1

Views

Author

David Cleaver, Mar 16 2025

Keywords

Comments

Self-descriptive sequence: even indexed terms are the sequence itself, odd indexed terms are the prime numbers.
This is an r1k1 fractal sequence, where r1k1 means: remove 1 term, keep 1 term, repeat. The Removed terms are the sequence that has been fractalized, and the Kept terms are the original fractal sequence.
This fractal sequence is also a Kimberling fractal sequence because if you delete the first occurrence of each term, the remaining sequence is the same as the original.

Crossrefs

Programs

  • Mathematica
    a[n_] := Prime[(n/2^IntegerExponent[n, 2] + 1)/2]; Array[a, 100] (* Amiram Eldar, Mar 21 2025 *)

Formula

a(2n) = a(n); a(2n-1) = A000040(n), n >= 1.
a(n) = A000040(A003602(n)).
Showing 1-2 of 2 results.