%I #6 Feb 18 2019 04:09:36

%S 6,61,613,6131

%N a(n) is the smallest n-digit prime formed by appending a digit to a(n-1); a(1)=6.

%C There is no prime a(5) since all the integers from 61310 to 61319 are composite.

%p A160751 := proc(n) option remember ; local d; if n =1 then 6; else for d from 1 to 9 by 2 do if isprime(10*procname(n-1)+d) then RETURN( 10*procname(n-1)+d ) ; fi; od: RETURN(-1) ; fi; end: seq(A160751(n),n=1..10) ; # _R. J. Mathar_, May 26 2009

%Y Cf. A000040, A160674.

%K base,easy,fini,full,nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, May 25 2009

%E Corrected by _R. J. Mathar_, May 26 2009