editing

approved

a(16)=0 since the concatenation of 53 with itself, followed by a 9, is always composite. a(36), if it exists, has more than 12000 digits. - Giovanni Resta, Apr 07 2006

approved

editing

_Amarnath Murthy (amarnath_murthy(AT)yahoo.com), _, Mar 28 2004

More terms from _Sam Alexander (amnalexander(AT)yahoo.com), _, Jan 09 2005

a(16)=0 since the concatenation of 53 with itself, followed by a 9, is always composite. a(36), if exists, has more than 12000 digits. - _Giovanni Resta (g.resta(AT)iit.cnr.it), _, Apr 07 2006

More terms from _Giovanni Resta (g.resta(AT)iit.cnr.it), _, Apr 07 2006

29, 0, 59, 79, 11119, 139, 179, 199, 239, 29292929292929299, 31319, 379, 419, 439, 479, 0, 599, 619, 67679, 719, 739, 797979799, 839, 89899, 979797979, 1019, 1039, 1071071071079, 1091091091099, 1131139, 1279, 1319, 1371371371379, 1399, 1499

Next prime, a(16)=0 since the concatenation of 53 with itself, followed by a 9, is always composite. a(36), if it exists, is > 10^72has more than 12000 digits. - Sam Alexander Giovanni Resta (amnalexanderg.resta(AT)yahooiit.cnr.comit), Jan 09 2005Apr 07 2006

base,nonn,new

More terms from Giovanni Resta (g.resta(AT)iit.cnr.it), Apr 07 2006

Least Smallest prime of the form concatenation of prime(n) with itself followed by a 9, or 0 if no such prime exists.

base,nonn,new

Least prime of the form concatenation of prime(n) with itself followed by a 9. a(2) =, or 0 if no such prime exists.

29, 0, 59, 79, 11119, 139, 179, 199, 239, 29292929292929299, 31319, 379, 419, 439, 479

Next prime, if it exists, is > 10^72. - Sam Alexander (amnalexander(AT)yahoo.com), Jan 09 2005

base,more,nonn,new

More terms from Sam Alexander (amnalexander(AT)yahoo.com), Jan 09 2005

Least prime of the form concatenation of prime(n) with itself followed by a 9. a(2) =0.

29, 0, 59, 79, 11119, 139, 179, 199

1,1

Cf. A092992, A092993, A092994.

base,more,nonn

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 28 2004

approved