This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A109944 #6 Nov 29 2017 17:42:44 %S A109944 1,20,30,41,50,61,70,83,97,101,110,127,130,149,151,163,170,181,190, %T A109944 2003,211,223,230,241,251,263,271,281,290,307,310,3203,331,347,353, %U A109944 367,370,383,397,401,410,421,430,443,457,461,470,487,491,503,5101,521,530,541 %N A109944 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 A109944 If n is composite, a(n) = A018800(n). - _David Wasserman_, Jul 19 2005 %K A109944 base,easy,nonn %O A109944 1,2 %A A109944 _Amarnath Murthy_, Jul 19 2005 %E A109944 More terms from _David Wasserman_, Jul 19 2005