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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A378309 a(n) = A010051(n) + A001222(n).

Original entry on oeis.org

0, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 4, 2, 3, 2, 3, 2, 2, 2, 4, 2, 2, 3, 3, 2, 3, 2, 5, 2, 2, 2, 4, 2, 2, 2, 4, 2, 3, 2, 3, 3, 2, 2, 5, 2, 3, 2, 3, 2, 4, 2, 4, 2, 2, 2, 4, 2, 2, 3, 6, 2, 3, 2, 3, 2, 3, 2, 5, 2, 2, 3, 3, 2, 3, 2, 5, 4, 2, 2, 4, 2, 2, 2, 4, 2, 4
Offset: 1

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Author

Paolo Xausa, Nov 22 2024

Keywords

Crossrefs

First differences of A113903.

Programs

  • Mathematica
    Array[Boole[PrimeQ[#]] + PrimeOmega[#] &, 100]
  • PARI
    a(n) = isprime(n) + bigomega(n); \\ Michel Marcus, Nov 23 2024

Formula

a(n) = A113903(n) - A113903(n-1).
a(n) = 2 for prime n.
a(2*k) = A073093(k), for k >= 2.
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