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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A349228 Products of three consecutive terms of A349227: a(n) = A349227(n) * A349227(n+1) * A349227(n+2).

Original entry on oeis.org

1, 2, 4, 8, 12, 6, 3, 5, 10, 20, 16, 24, 36, 9, 15, 25, 50, 30, 18, 27, 45, 60, 40, 32, 48, 72, 54, 63, 21, 7, 11, 22, 44, 28, 14, 35, 55, 110, 66, 42, 84, 56, 64, 80, 120, 75, 90, 150, 180, 210, 126, 105, 135, 225, 270, 240, 96, 112, 70, 140, 100, 160, 200
Offset: 1

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Author

Rémy Sigrist, Nov 11 2021

Keywords

Comments

All terms are distinct.
Is this sequence a permutation of the natural numbers?

Examples

			a(5) = A349227(5) * A349227(6) * A349227(7) = 2 * 2 * 3 = 12.
		

Crossrefs

Programs

  • PARI
    s=0; pp=p=1; for (n=1, 63, for (v=1, oo, if (!bittest(s, q=pp*p*v), print1 (q", "); s+=2^q; pp=p; p=v; break)))
    
  • Python
    def aupton(terms):
        A349227lst, plst, pset = [1, 1], [], set()
        for n in range(terms):
            p = p2 = A349227lst[-1]*A349227lst[-2]
            while p in pset: p += p2
            A349227lst.append(p//p2); plst.append(p); pset.add(p)
        return plst
    print(aupton(63)) # Michael S. Branicky, Nov 12 2021
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