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A139067 Primes whose decimal expansion consists of a string of 2's followed by a string of 3's. 6
2, 3, 23, 223, 233, 2333, 23333, 2222333, 22222223, 223333333, 22222222223, 22222223333, 22222333333, 22223333333, 23333333333, 222223333333, 23333333333333333, 2222222222222233333, 2222222222333333333 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..19.

MATHEMATICA

With[{nn=20}, Sort[Select[Flatten[Table[FromDigits[Join[Table[2, {i}], Table[3, {j}]]], {i, 0, nn}, {j, 0, nn}]], PrimeQ]]] (* Harvey P. Dale, Jan 30 2013 *)

CROSSREFS

Cf. A020458, A141470, A141471, A141472.

Sequence in context: A260126 A260125 A020458 * A099656 A157733 A235934

Adjacent sequences:  A139064 A139065 A139066 * A139068 A139069 A139070

KEYWORD

nonn,base

AUTHOR

Paul Curtz, Jun 05 2008

EXTENSIONS

Entry revised by Ray Chandler and N. J. A. Sloane, Aug 14 2008

STATUS

approved

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Last modified November 14 19:59 EST 2019. Contains 329128 sequences. (Running on oeis4.)