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.

A325454 a(n) is the digit sum of the n-th Niven number (or Harshad number).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 3, 9, 2, 3, 6, 9, 3, 9, 4, 6, 9, 12, 5, 9, 6, 9, 7, 9, 8, 9, 12, 9, 1, 3, 9, 2, 3, 4, 6, 9, 3, 9, 6, 7, 9, 5, 9, 6, 8, 9, 12, 9, 9, 9, 10, 12, 15, 18, 2, 3, 6, 9, 11, 3, 9, 4, 6, 8, 9, 12, 5, 9, 6, 9, 13, 9, 9, 12, 14, 9, 10, 15
Offset: 1

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Author

Felix Fröhlich, Sep 06 2019

Keywords

Crossrefs

Programs

  • PARI
    is_a005349(n) = n%sumdigits(n)==0
    terms(n) = my(i=0); for(k=1, oo, if(i>=n, break); if(is_a005349(k), print1(sumdigits(k), ", "); i++))
    terms(80) \\ Print initial 80 terms

Formula

a(n) = A005349(n)/A113315(n).
a(n) = A007953(A005349(n)).