

A096221


a(n) is the number of distances used by minimal primecomplete rulers for the first n primes.


1




OFFSET

0,2


COMMENTS

The best known upper bounds for a(915) 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(915)
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,changed


AUTHOR

Ray G. Opao, Jul 29 2004


STATUS

approved



