login
a(n) = smallest number which has in its Spanish name the letter "e" in the n-th position,or -1 if no such number exists.
0

%I #2 Mar 31 2012 14:00:43

%S -1,0,3,11,7,15,14,17,23,17,27,43,37,47,57,117,127,143,137,147,157,

%T 243,237,247,257,357,447,457

%N a(n) = smallest number which has in its Spanish name the letter "e" in the n-th position,or -1 if no such number exists.

%C a(2)=cEro, a(3)=trEs, a(4)=oncE

%K word,sign

%O 1,3

%A _Claudio Meller_, Aug 26 2009