A088619 Numbers k such that the concatenation of 1, k and k^2 is prime.

3, 11, 21, 29, 39, 47, 59, 69, 101, 111, 131, 149, 171, 183, 197, 213, 231, 243, 249, 251, 297, 299, 317, 323, 329, 369, 387, 401, 411, 423, 431, 461, 501, 521, 527, 533, 537, 539, 543, 593, 651, 657, 669, 717, 741, 743, 779, 819, 867, 869, 873, 897, 939, 981

Offset

1,1

Links

Table of n, a(n) for n=1..54.

Example

3 is a member as 139 is a prime. 11 is a member as 111121 (concatenation of 1,11 and 121) is prime.

Mathematica

Select[ Range[1000], PrimeQ[ FromDigits[ Join[ IntegerDigits[ #^0], IntegerDigits[ # ], IntegerDigits[ #^2]]]] &]

Crossrefs

Cf. A068702.

Sequence in context: A363012 A006876 A031239 * A031318 A082485 A322595

Adjacent sequences: A088616 A088617 A088618 * A088620 A088621 A088622

Keyword

base,nonn

Author

Amarnath Murthy, Oct 17 2003

Extensions

Edited and extended by Robert G. Wilson v and Ray Chandler, Oct 18 2003

Status

approved