A090262 Numbers n such that the strings n1n and 1n1 are both prime.

3, 9, 17, 29, 47, 51, 81, 87, 113, 117, 131, 141, 201, 239, 291, 333, 359, 371, 393, 443, 459, 489, 509, 539, 573, 623, 663, 681, 749, 819, 821, 873, 903, 947, 1071, 1077, 1161, 1269, 1533, 1563, 1589, 1613, 1637, 1673, 1767, 1773, 1821, 1841, 1883, 1959, 1977

Offset

1,1

Links

Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Example

9 is a member as 919 and 191 are both prime.

Crossrefs

Cf. A090263, A090264, A090265.

Sequence in context: A018466 A171152 A035107 * A190815 A006459 A349489

Adjacent sequences: A090259 A090260 A090261 * A090263 A090264 A090265

Keyword

base,nonn

Author

Amarnath Murthy, Nov 28 2003

Extensions

More terms from mohammed bouayoun (bouyao(AT)wanadoo.fr), Feb 02 2004

Status

approved