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.

A130789 The primes prime(n) sorted according to increasing prime(n)/prime(n+1).

Original entry on oeis.org

3, 7, 2, 5, 13, 23, 19, 31, 11, 47, 113, 17, 53, 37, 61, 43, 89, 73, 83, 139, 29, 199, 67, 211, 181, 79, 41, 293, 131, 317, 241, 97, 151, 103, 157, 109, 167, 283, 173, 523, 59, 127, 337, 71, 233, 467, 1327, 163, 409, 251, 421, 509, 257, 263, 887, 359, 271, 193
Offset: 1

Views

Author

R. J. Mathar, Jul 15 2007

Keywords

Comments

Or: primes sorted according to decreasing ratio A001223(n)/A000040(n). All values are conjectural, derived from the finite list up to prime(200000): large prime gaps at higher indices may still insert numbers above prime(200000) at low positions of the sequence.
Using a table of prime gaps, it is easy to determine that the sequence is correct for all primes < 10^18. - T. D. Noe, Jul 17 2007

Examples

			3/5 < 7/11 < 2/3 < 5/7 < 13/17 < 23/29 < 19/23 < 31/37 < 11/13 < ...
Numerators of this chain of inequalities define the sequence.
		

Crossrefs

Programs

  • Mathematica
    With[{nn=60},Take[Transpose[SortBy[Partition[Prime[Range[20*nn]],2,1], #[[1]]/ #[[2]]&]][[1]],nn]] (* Harvey P. Dale, Dec 03 2014 *)