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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
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
KEYWORD
nonn,more
AUTHOR
Ray G. Opao, Jul 29 2004
STATUS
approved

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