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%I #14 Aug 17 2017 22:33:30
%S 3,23,211,2003,20011,200003,3000017,20000003,200000033,2000000011,
%T 20000000089,300000000077,2000000000003,20000000000021,
%U 400000000000063,2000000000000021,50000000000000051,200000000000000003
%N a(n) = smallest n-digit prime which differs from the previous n-digit prime at every corresponding digit (or 0 if no such prime exists).
%C For n > 1, a(n), if it exists, is of the form nextprime(t*10^(n-1)) for some t, 2 <= t <= 9. [_Max Alekseyev_, Apr 23 2010]
%e 2003 is a term as the previous prime 1999 differs at every corresponding position (1,2), (9,0), (9,0), (9,3).
%t Table[SelectFirst[Partition[Prime@ Range[PrimePi@ NextPrime[10^n], PrimePi[10^(n + 1) - 1]], 2, 1], AllTrue[Transpose@ {IntegerDigits[#1], IntegerDigits[#2]}, UnsameQ @@ # &] & @@ # &], {n, 0, 7}] [[All, -1]] (* _Michael De Vlieger_, Aug 14 2017 *)
%o (PARI) { a(n) = local(L,U,aa,bb); if(n==1, return(3)); for(t=2,9, L=precprime(t*10^(n-1)); U=nextprime(t*10^(n-1)); aa=Vec(Str(L)); bb=Vec(Str(U)); if(sum(i=1,#aa,aa[i]!=bb[i])==#aa,return(U)); ); 0 } \\ _Max Alekseyev_, Apr 23 2010
%Y Cf. A114016.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Nov 12 2005
%E 2 more terms from _R. J. Mathar_, Aug 31 2007
%E More terms from _Max Alekseyev_, Apr 23 2010
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