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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A071316 Sum of terms of continued fraction expansion of frac((3/2)^n).

Original entry on oeis.org

2, 4, 5, 16, 10, 10, 17, 13, 20, 74, 113, 32, 25, 76, 55, 31, 44, 86, 74, 46, 42, 100, 402, 115, 63, 71, 104, 143, 489, 346, 96, 78, 68, 87, 167, 196, 116, 95, 76, 123, 109, 108, 141, 176, 141, 133, 260, 1038, 4748, 5731, 1162, 285, 189, 248, 478, 399, 163, 154
Offset: 1

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Author

Paul D. Hanna, Jun 11 2002

Keywords

Comments

What is the rate of growth of this sequence?

Examples

			a(3) = 5 since frac((3/2)^3) = [0;2,1,2] and a(3) = 2 + 1 + 2.
		

References

  • S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 192-199.

Crossrefs

Programs

  • PARI
    a(n) = {cf = contfrac((3/2)^n); return (sum(i=2, #cf, cf[i]));} \\ Michel Marcus, Aug 01 2013

Extensions

Name corrected by Sean A. Irvine, Jul 11 2024

A071915 Number of 1's in the continued fraction expansion of (3/2)^n.

Original entry on oeis.org

0, 0, 1, 0, 2, 3, 3, 6, 3, 5, 1, 2, 8, 2, 3, 5, 2, 3, 3, 6, 10, 8, 6, 4, 2, 3, 6, 5, 2, 9, 12, 7, 17, 10, 7, 9, 8, 10, 13, 13, 10, 12, 14, 9, 11, 10, 11, 6, 9, 5, 3, 13, 13, 19, 18, 13, 8, 12, 15, 14, 18, 7, 19, 19, 17, 15, 13, 14, 16, 13, 20, 16, 10, 20, 25, 17, 19, 14, 19, 14, 18, 22
Offset: 1

Views

Author

Benoit Cloitre, Jun 13 2002

Keywords

Comments

It seems that lim n ->infinity a(n)/n = 0.2... << (log(4)-log(3))/log(2) = 0.415... the expected density of 1's (cf. measure theory of continued fraction).

Examples

			The continued fraction of (3/2)^24 is [16834, 8, 1, 10, 2, 25, 1, 3, 1, 1, 57, 6] which contains 4 "1's", hence a(24)=4.
		

Crossrefs

Programs

  • Mathematica
    a[1] = 0; a[n_] := Count[ContinuedFraction[(3/2)^n], 1]; Array[a, 100] (* Amiram Eldar, Sep 05 2020 *)
  • PARI
    for(n=1,200,s=contfrac(frac((3/2)^n)); print1(sum(i=1,length(s),if(1-component(s,i),0,1)),","))
Showing 1-2 of 2 results.