A068714 Primes formed from a concatenation of 2 and 3^k for some k.

23, 29, 227, 281, 2243, 2729, 26561, 219683, 24782969, 210460353203, 2282429536481, 27625597484987, 250031545098999707, 279766443076872509863361, 2239299329230617529590083, 219383245667680019896796723, 2202755595904452569706561330872953769

Offset

0,1

Links

Table of n, a(n) for n=0..16.

Example

2243 is a member as it is a concatenation of 2 and 243 = 3^5.

Mathematica

Select[Table[FromDigits[Prepend[IntegerDigits[3^n], 2]], {n, 75}], PrimeQ] (* Jayanta Basu, May 22 2013 *)

Crossrefs

Cf. A068712.

Sequence in context: A229176 A232726 A029541 * A344127 A036267 A107934

Adjacent sequences: A068711 A068712 A068713 * A068715 A068716 A068717

Keyword

nonn,base

Author

Amarnath Murthy, Mar 05 2002

Extensions

More terms from Sascha Kurz, Mar 17 2002

Status

approved