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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A350606 a(n) is the number of elements in row n of A350605.

Original entry on oeis.org

1, 3, 7, 15, 30, 60, 119, 237, 472, 940, 1874, 3740, 7469, 14918, 29805, 59561, 119043, 237966, 475750, 951213, 1901981, 3803271, 7605468, 15209251, 30415896, 60827703, 121648985, 243287862, 486559789, 973094453, 1946149237
Offset: 1

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Author

N. J. A. Sloane, Jan 12 2022

Keywords

Comments

It would be nice to have a formula.
Conjecture: a(n) is approximately = k*2^(n-5) for n>4. - Bill McEachen, Jul 30 2024

Crossrefs

Cf. A350605.

Programs

  • Python
    from itertools import chain, islice
    def A350606_gen(): # generator of terms
        s = {1}
        while True:
            yield len(s)
            s = set(chain.from_iterable((x,2*x+1,3*x+1) for x in s))
    A350606_list = list(islice(A350606_gen(),20)) # Chai Wah Wu, Jan 12 2022

Extensions

a(14)-a(31) from Chai Wah Wu, Jan 12 2022
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