A190502 Number of Ramanujan primes <= 2^n.
0, 1, 1, 1, 2, 4, 7, 13, 23, 42, 75, 137, 255, 463, 872, 1612, 3030, 5706, 10749, 20387, 38635, 73584, 140336, 268216, 513705, 985818, 1894120, 3645744, 7027290, 13561906, 26207278, 50697533, 98182656, 190335585, 369323301, 717267167, 1394192236, 2712103833
Offset: 0
Keywords
Links
- Dana Jacobsen, Table of n, a(n) for n = 0..56
Programs
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PARI
\\ With RR[.] is a list of A104272(.). The output of this program is n, a(n), and RR[a(n)]. j=0; while(2^j
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Perl
use ntheory ":all"; sub a190502 { scalar(@{ramanujan_primes(1 << shift)}) } say a190502($) for 0..20; # _Dana Jacobsen, Dec 19 2015 -
Perl
use ntheory ":all"; my $t = 0; for my $e (1..32) { $t += scalar(@{ramanujan_primes(2**($e-1)+1,2**$e)}); say "$e $t" } # Dana Jacobsen, Dec 19 2015 -
Perl
use ntheory ":all"; say ramanujan_prime_count(2**$) for 0..47; # _Dana Jacobsen, Jan 03 2016
Extensions
Extended by T. D. Noe, May 11 2011
Extended to n = 32 by John W. Nicholson, Dec 01 2012
a(33)-a(41) from Dana Jacobsen, Dec 19 2015