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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A309430 a(n) = a(n-a(n-1)) + a(n-a(n-4)), with a(n) = ceiling(2*n/3) for n <= 7.

Original entry on oeis.org

1, 2, 2, 3, 4, 4, 5, 6, 6, 7, 7, 8, 9, 9, 10, 10, 11, 11, 12, 13, 13, 13, 14, 14, 15, 16, 16, 17, 17, 18, 19, 19, 19, 20, 20, 21, 21, 22, 23, 23, 24, 24, 25, 25, 26, 26, 26, 27, 27, 28, 29, 29, 30, 30, 31, 31, 32, 33, 33, 33, 34, 34, 35, 36, 36, 37, 37, 38, 38, 38, 39, 39, 40, 41, 41, 41, 42, 42, 43, 44, 44
Offset: 1

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Author

Altug Alkan, Aug 01 2019

Keywords

Comments

A slow solution to Hofstadter V recurrence.
Numbers k such that a(k) < A063882(k) are 1654, 1721, 1925, ...

Crossrefs

Programs

  • PARI
    q=vector(100); for(n=1, 7, q[n]=ceil(2*n/3));for(n=8, #q, q[n]=q[n-q[n-1]] +q[n-q[n-4]]); q

Formula

a(n+1) - a(n) = 0 or 1 for all n >= 1.
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