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A192821 3-Ramanujan primes; the interval (x/2,x] has at least n 2-Ramanujan primes for x >= a(n) but not for x = a(n)-1. 6
41, 149, 227, 229, 233, 569, 571, 587, 593, 641, 643, 821, 937, 941, 1367, 1373, 1423, 1439, 1481, 1549, 1553, 2207, 2237, 2239, 2267, 2269, 2273, 2281, 2333, 2339, 2347, 2377, 2617, 2657, 3251, 3257, 3259, 3299, 3343, 3347, 3449, 3581, 3583, 3607, 3613 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It is conjectured that primepi(a(n)) < 10*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 26 2011

Subsequence of the 2-Ramanujan primes A192820, by the minimality of a(n). - Jonathan Sondow, Aug 21 2012

LINKS

Table of n, a(n) for n=1..45.

CROSSREFS

Cf. A104272 (Ramanujan primes), A192820 (2-Ramanujan primes), A192822, A192823, A192824.

Sequence in context: A146330 A146350 A050954 * A141957 A108016 A142630

Adjacent sequences:  A192818 A192819 A192820 * A192822 A192823 A192824

KEYWORD

nonn

AUTHOR

T. D. Noe, Jul 11 2011

EXTENSIONS

Definition clarified by Jonathan Sondow, Aug 21 2012

STATUS

approved

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Last modified August 25 03:10 EDT 2019. Contains 326318 sequences. (Running on oeis4.)