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.

A128437 a(n) = floor((numerator of H(n))/n), where H(n) = Sum_{k=1..n} 1/k is the n-th harmonic number.

Original entry on oeis.org

1, 1, 3, 6, 27, 8, 51, 95, 792, 738, 7610, 7168, 88153, 83695, 79717, 152284, 2478954, 793016, 14489252, 2791756, 898002, 867872, 19318117, 56159289, 1362100898, 1322913164, 11575416740, 11264449603, 318174017634, 310156094338
Offset: 1

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Author

Leroy Quet, Mar 03 2007

Keywords

Comments

Numerator of H(n) is a(n)*n + A126083(n).

Examples

			a(6) = 8 because H(6) = 49/20 and floor(49/6) = 8.
		

Crossrefs

Programs

  • Maple
    H:=n->sum(1/k,k=1..n): a:=n->floor(numer(H(n))/n): seq(a(n),n=1..35); # Emeric Deutsch, Mar 22 2007
  • Mathematica
    seq = {}; s = 0; Do[s += 1/n; AppendTo[seq, Floor[Numerator[s]/n]], {n, 1, 30}]; seq (* Amiram Eldar, Dec 01 2020 *)
  • PARI
    a(n) = numerator(sum(k=1, n, 1/k))\n; \\ Michel Marcus, Feb 01 2019
    
  • Python
    from sympy import harmonic
    def A128437(n): return harmonic(n).p//n # Chai Wah Wu, Sep 27 2021

Extensions

More terms from Emeric Deutsch, Mar 22 2007