A124117 - OEIS

%I #4 Mar 30 2012 17:34:57

%S 21,129,1003,10681,101829,1020831,10251129,100780743,1051460221,

%T 10153541853,103257526729,1483112006019

%N a(n) the smallest composite number of n+1 digits that becomes a prime by incrementing any one of the higher order digits.

%e a(4)=10681 as 20681, 11681, 10781 and 10691 are prime

%K hard,nonn,base

%O 1,1

%A Anton Vrba (antonvrba(AT)yahoo.com), Nov 28 2006

%E a(11)-a(12) from _Donovan Johnson_, Nov 24 2010