A069691 - OEIS

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

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OFFSET

0,1

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

LINKS

Robert Price, Table of n, a(n) for n = 0..10000

Index entries for primes involving decimal expansion of n

EXAMPLE

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

CROSSREFS

Cf. A032734.

Sequence in context: A214527 A084413 A248533 * A084414 A164937 A105992

Adjacent sequences: A069688 A069689 A069690 * A069692 A069693 A069694

KEYWORD

nonn,base

AUTHOR

Amarnath Murthy, Apr 06 2002

EXTENSIONS

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

STATUS

approved