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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A028559 Palindromes of the form k*(k+5).

Original entry on oeis.org

0, 6, 66, 414, 696, 41814, 42224, 666666, 4282824, 4754574, 4881884, 416343614, 630939036, 4159669514, 6817557186, 42877777824, 4163250523614, 4783601063874, 4986733376894, 47431877813474, 6333914444193336, 44653247574235644, 62141509790514126
Offset: 1

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Keywords

Crossrefs

Programs

  • Python
    from itertools import count, islice
    def ispal(n): s = str(n); return s == s[::-1]
    def agen():
        for k in count(0):
            if ispal(k*(k+5)):
                yield k*(k+5)
    print(list(islice(agen(), 20))) # Michael S. Branicky, Jan 30 2022

Formula

a(n) = A028558(n) * (A028558(n) + 5). - Michael S. Branicky, Jan 30 2022

Extensions

a(21) and beyond from Michael S. Branicky, Jan 30 2022
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