|
Search: id:A074810
|
|
|
| A074810 |
|
Number of primes between n and 2n (inclusive) = largest prime factor of n. |
|
+0
1
|
|
| 1, 2, 4, 8, 9, 28, 65, 114, 174, 186, 246, 623, 1784, 1832, 1912, 5121, 13810, 14090, 39413, 40403, 808822, 809858, 810026
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
EXAMPLE
|
a(6) = 28 because there are 7 primes between n = 28 and 2n = 56: 29, 31, 37, 41, 43, 47, 53; and the largest prime dividing 28 is 7.
|
|
MAPLE
|
with(numtheory): a:=proc(n) if pi(2*n)-pi(n-1)=factorset(n)[nops(factorset(n))] then n else fi end: 1, seq(a(n), n=2..1000); (Deutsch)
|
|
CROSSREFS
|
Cf. A035250, A006530.
Sequence in context: A140141 A088274 A118418 this_sequence A028984 A153181 A043706
Adjacent sequences: A074807 A074808 A074809 this_sequence A074811 A074812 A074813
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Jason Earls (zevi_35711(AT)yahoo.com), Sep 08 2002
|
|
EXTENSIONS
|
More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 05 2006
|
|
|
Search completed in 0.002 seconds
|
