A214756 a(n) = largest Ramanujan prime R_k in A104272 that is <= A002386(n).

2, 2, 2, 17, 71, 107, 503, 881, 1103, 1301, 9521, 15671, 19543, 31387, 155849, 360289, 370061, 492067, 1349147, 1356869, 2010553, 4652239, 17051297, 20831119, 47326519, 122164649, 189695483, 191912659

Offset

1,1

Comments

While many values in A214757(n) are equal to A000101(n), here it seems the only value such that A002386(n) is equal to a(n) is a(1) = R_k = A002386(1) = 2.

See "Let rho(m) = A179196(m)" comment at A001223.

Links

Dana Jacobsen, Table of n, a(n) for n = 1..59

Example

A104272(94) = 1301 < 1327 = A002386(10), so a(10) = 1301.

Prog

(Perl) use ntheory ":all";  sub a_from_2386 { my $n = shift; $n = prev_prime($n) while !is_ramanujan_prime($n); $n } # Dana Jacobsen, Jul 13 2016
(Perl) perl -Mntheory=:all -nE 'my $n=$1 if /(\d+)$/; $r=ramanujan_primes($n>1e6 ? $n-1e6 : 2, $n); say ++$x, " ", $r->[-1]; ' b002386.txt # Dana Jacobsen, Jul 13 2016

Crossrefs

Cf. A002386, A104272, A001223.

Cf. A214925, A214926, A214757, A214924.

Sequence in context: A369011 A346079 A195871 * A079007 A349642 A064215

Adjacent sequences: A214753 A214754 A214755 * A214757 A214758 A214759

Keyword

nonn

Author

John W. Nicholson, Jul 27 2012

Extensions

Edited by N. J. A. Sloane, Aug 06 2012

a(16)-a(28) from Donovan Johnson, Nov 04 2012

Status

approved