

A192823


5Ramanujan primes; the interval (x/2,x] has at least n 4Ramanujan primes for x >= a(n) but not for x = a(n)1.


6



1367, 1373, 1423, 1439, 2207, 2237, 3251, 3257, 3259, 3299, 5639, 8059, 12739, 12781, 12799, 12809, 12821, 12823, 12829, 12907, 12911, 12917, 12919, 12953, 13147, 13163, 13171, 13669, 13687, 13691, 13693, 14009, 14029, 14057, 14081, 14143, 31957, 32183
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OFFSET

1,1


COMMENTS

It is conjectured that primepi(a(n)) < 50*n for large n.  T. D. Noe, Aug 26 2011
The sequence is only conjectural without a proof of an upper bound on a(n) (like the bound A104272(n) < prime(3*n) proved by Laishram and used in computing Ramanujan primes).  Jonathan Sondow, Aug 27 2011
Subsequence of the 4Ramanujan primes A192822, by the minimality of a(n).  Jonathan Sondow, Aug 21 2012


LINKS

Table of n, a(n) for n=1..38.


CROSSREFS

Cf. A104272 (Ramanujan primes), A192820, A192821, A192822 (4Ramanujan primes), A192824.
Sequence in context: A180089 A020409 A231268 * A221932 A331464 A167724
Adjacent sequences: A192820 A192821 A192822 * A192824 A192825 A192826


KEYWORD

nonn


AUTHOR

T. D. Noe, Jul 11 2011


EXTENSIONS

Definition clarified by Jonathan Sondow, Aug 21 2012


STATUS

approved



