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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A376315 Positive numbers k such that 2*k^k is a cube.

Original entry on oeis.org

2, 4, 128, 256, 686, 1372, 2000, 4000, 4394, 8192, 8788, 13718, 16384, 21296, 27436, 31250, 42592, 43904, 59582, 62500, 78608, 87808, 101306, 119164, 128000, 157216, 159014, 194672, 202612, 235298, 256000, 281216, 318028, 332750, 389344, 390224, 453962, 470596
Offset: 1

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Author

Chai Wah Wu, Sep 20 2024

Keywords

Comments

{a(n)} UNION A376291 = positive numbers k such that k^k is not a cube and can be expressed as (x^3 + y^3)/2 for nonnegative integers x, y.
All terms are even.

Crossrefs

Programs

  • Python
    from itertools import count, islice
    from sympy import factorint
    def A376315_gen(startvalue=2): # generator of terms >= startvalue
        for k in count(max(startvalue+(startvalue&1),2),2):
            f = {p:k*e for p,e in factorint(k).items()}
            f[2] += 1
            if not any(v%3 for v in f.values()):
                yield k
    A376315_list = list(islice(A376315_gen(),30))
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