A069691 Smallest prime with internal digits = n; or 0 if no such number exists.

101, 113, 127, 131, 149, 151, 163, 173, 181, 191, 1103, 1117, 1123, 2131, 2141, 1151, 1163, 1171, 1181, 1193, 1201, 1213, 1223, 1231, 1249, 1259, 2267, 1277, 1283, 1291, 1301, 1319, 1321, 2333, 2341, 2351, 1361, 1373, 1381, 1399, 1409, 2411, 1423, 1433, 1447

Offset: 0

Author

Amarnath Murthy, Apr 06 2002

Keywords

• nonn
• base
• changed

Comments

By placing one digit on both sides of n one get 36 different numbers that might be primes ( 1 to 9 on left and 1,3,7,9 on right). If none of these numbers is a prime then a(n) = 0.

The smallest value of n for which a(n) = 0 is 2437 = A032734(0). - Rick L. Shepherd and Reinhard Zumkeller, Jul 17 2002

Examples

			a(25) = 1259 is prime with internal digits =25.
		

Links

• Robert Price, Table of n, a(n) for n = 0..10000
• Index entries for primes involving decimal expansion of n

Crossrefs

Cf. A032734, A030665, A069691, A077501, A084413.

Extensions

Corrected and extended by Larry Reeves, Rick L. Shepherd and Reinhard Zumkeller, Jul 17 2002