A276199 Smallest prime that begins with at least n digits of Pi.

3, 31, 31469, 314107, 314159, 314159, 314159207, 3141592603, 31415926541, 314159265307, 314159265359, 3141592653581, 314159265358909, 3141592653589711, 31415926535897921, 314159265358979347, 3141592653589793239, 3141592653589793239, 314159265358979323861

Offset: 1

Author

José Eduardo Gaboardi de Carvalho, Aug 24 2016

Keywords

• nonn
• base

Examples

			a(7) = 314159207, begins with first 7 digits of Pi = 3.141592653...
		

Links

• Dana Jacobsen, Table of n, a(n) for n = 1..997 (first 28 terms from José Eduardo Gaboardi de Carvalho)

Crossrefs

Cf. A005042.

Programs

Perl

use ntheory ":all"; sub a276199 { my $l=shift; my $p="3".substr(Pi($l+20),2,$l-1); for my $dig (0 .. 20) { my $add = "0" x $dig; do { return "$p$add" if is_prime("$p$add"); } while length(++$add) == $dig; } } # Dana Jacobsen, Aug 30 2016