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 A113580 #11 Dec 05 2013 19:57:07
%S A113580 1,2,3,5,7,11,13,17,19,23,3,4,5,7,9,13,15,19,21,25,4,5,6,8,10,14,16,
%T A113580 20,22,26,6,7,8,10,12,16,18,22,24,28,8,9,10,12,14,18,20,24,26,30,12,
%U A113580 13,14,16,18,22,24,28,30,34,14,15,16,18,20,24,26,30,32,36,18,19,20,22,24,28
%N A113580 Define prime(0) = 1; then a(n) = sum prime(d), where d ranges over the decimal digits of n.
%H A113580 Vincenzo Librandi, <a href="/A113580/b113580.txt">Table of n, a(n) for n = 0..1000</a>
%e A113580 a(123) = prime(1) + prime(2) + prime(3) = 2 + 3 + 5 = 10.
%e A113580 a(10001) = 2 + 1 + 1 + 1 + 2 = 7.
%t A113580 f[n_] := Plus @@ (IntegerDigits[n] /. {0 -> 1, 1 -> 2, 2 -> 3, 3 -> 5, 4 -> 7, 5 -> 11, 6 -> 13, 7 -> 17, 8 -> 19, 9 -> 23}); Table[ f[n], {n, 0, 75}] (* _Robert G. Wilson v_ *)
%Y A113580 Cf. A113581; first occurrence in A113736.
%K A113580 nonn,base
%O A113580 0,2
%A A113580 _Amarnath Murthy_, Nov 06 2005
%E A113580 More terms from _Robert G. Wilson v_, Nov 08 2005