The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A096221 a(n) is the number of distances used by minimal prime-complete rulers for the first n primes. 1
 1, 2, 3, 5, 7, 10, 13, 15, 18 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The best known upper bounds for a(9-15) are 22, 25, 29, 33, 37, 41, 45. See attached file for the corresponding rulers. - Dmitry Kamenetsky, Mar 09 2018 LINKS Table of n, a(n) for n=0..8. Dmitry Kamenetsky, Upper bounds and their rulers for a(9-15) Carlos Rivera, The Prime Puzzles & Problems Connection: Puzzle 172. Carlos Rivera, The Prime Puzzles & Problems Connection: Puzzle 914. EXAMPLE a(7)=15: there are 7 primes (2, 3, 5, 7, 11, 13, 17) and 8 ones. These rulers can generate every distance between 1 and 66, inclusive. There are two such rulers: 1.1.1.1.11.1.1.2.13.7.17.1.3.5.1 and 1.1.1.1.11.2.1.1.13.7.17.1.5.3.1 CROSSREFS Sequence in context: A090420 A162999 A064509 * A258084 A120367 A072831 Adjacent sequences: A096218 A096219 A096220 * A096222 A096223 A096224 KEYWORD nonn,more AUTHOR Ray G. Opao, Jul 29 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 1 16:12 EST 2024. Contains 370442 sequences. (Running on oeis4.)