A214506 - OEIS

%I #23 Feb 23 2014 02:52:57

%S 2,1,1,9,7,3,3,9,7,7,9,3,9,7,1,7,1,3,3,1,9,7,9,7,7,3,7,3,1,9,7,3,9,1,

%T 3,9,7,3,3,3,1,9,3,7,1,9,1,3,3,9,1,1,7,1,1,1,3,9,9,9,7,3,7,1,7,9,9,9,

%U 9,9,3,3,9,9,7,9,3,1,3,9,9,3,1,7,1,3

%N Last digit of the smallest prime number in base 10 with n digits.

%C The last digit of the first prime number in base 10 with n digits for n = 1, 2, 3 is 211, because 2 is the least with 1 digit, 11 the least with 2 digits, 101 the least with 3 digits. The concatenation, 211, is prime. This does not happen again through 24 digits. - _Jonathan Vos Post_, Jul 04 2012

%F a(1) = 2, and a(n) = A033873(n) mod 10 for n>1.

%F a(n) = A003617(n) mod 10. - _Michel Marcus_, Aug 06 2013

%t Table[Mod[NextPrime[10^n],10],{n,0,30}] (* _Harvey P. Dale_, Jan 25 2013 *)

%K nonn,base

%O 1,1

%A _Tjandra Satria Gunawan_, Jul 19 2012

%E More terms from _Harvey P. Dale_, Jan 25 2013