A234298 - OEIS

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A234298

Ramanujan prime R_k such that pi(R_(k+1)) - pi(R_k) are record values: record Ramanujan prime A190874(k).

2, 71, 181, 503, 2531, 5273, 9887, 11587, 55339, 174917, 225961, 534883, 2492311, 5409337, 130449773, 141833603, 212583797, 658046911, 1183597123, 2897211971, 5602581277, 46992178547, 70637059291, 158465541049, 182591976709, 339683208863

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OFFSET

1,1

COMMENTS

These are the primes preceding the unique values of A174641. That sequence is the start of a run of non-Ramanujan primes, so the previous prime is the Ramanujan prime. - Dana Jacobsen, Jul 14 2016

LINKS

Table of n, a(n) for n=1..26.

PROG

(Perl) perl -Mntheory=:all -nE 'my $n = $1 if /(\d+)$/; say ++$x, " ", prev_prime($n) unless $seen{$n}++; ' b174641.txt # Dana Jacobsen, Jul 14 2016

(Perl) use ntheory ":all"; my($max, $r)=(0, ramanujan_primes(1e7)); for (0..$#$r-1) { my $d=prime_count($r->[$_+1])-prime_count($r->[$_]); if ($d > $max) { say $r->[$_]; $max=$d; } } # Dana Jacobsen, Jul 14 2016

CROSSREFS

Record values are in A202186, index of A190874 at record terms in A202187, A202188 is the index of A168425 when A174641(n) = A168425(m); A202188(n) = m. A202187 is also the index of a(n).

Sequence in context: A293753 A164554 A141908 * A157368 A095935 A202813

Adjacent sequences: A234295 A234296 A234297 * A234299 A234300 A234301

KEYWORD

nonn

AUTHOR

John W. Nicholson, Dec 22 2013

EXTENSIONS

a(20) to a(26) from Dana Jacobsen, Jul 14 2016

STATUS

approved