%I #6 Nov 29 2017 17:42:44

%S 1,20,30,41,50,61,70,83,97,101,110,127,130,149,151,163,170,181,190,

%T 2003,211,223,230,241,251,263,271,281,290,307,310,3203,331,347,353,

%U 367,370,383,397,401,410,421,430,443,457,461,470,487,491,503,5101,521,530,541

%N a(1) = 1, a(n) = smallest prime number beginning with n if n is composite or vice versa. If n is prime a(n) = 10n.

%C If n is composite, a(n) = A018800(n). - _David Wasserman_, Jul 19 2005

%K base,easy,nonn

%O 1,2

%A _Amarnath Murthy_, Jul 19 2005

%E More terms from _David Wasserman_, Jul 19 2005