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 A113581 #12 May 11 2023 12:12:09
%S A113581 1,2,3,5,7,11,13,17,19,23,2,4,6,10,14,22,26,34,38,46,3,6,9,15,21,33,
%T A113581 39,51,57,69,5,10,15,25,35,55,65,85,95,115,7,14,21,35,49,77,91,119,
%U A113581 133,161,11,22,33,55,77,121,143,187,209,253,13,26,39,65,91,143,169,221,247,299
%N A113581 Define prime(0) = 1; then a(n) = product prime(d), where d ranges over all the decimal digits of n.
%C A113581 a(14) = 14. a(17) = 34.
%H A113581 Vincenzo Librandi, <a href="/A113581/b113581.txt">Table of n, a(n) for n = 0..1000</a>
%e A113581 a(123)= prime(1)*prime(2) *prime(3) = 2*3*5 = 30.
%t A113581 f[n_] := Times @@ (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, 69}] (* _Robert G. Wilson v_ *)
%Y A113581 Cf. A113580; A113735 gives positions where A113581(n)==0 (mod n).
%Y A113581 Fixed points are in A290675.
%K A113581 nonn,base
%O A113581 0,2
%A A113581 _Amarnath Murthy_, Nov 06 2005
%E A113581 More terms from _Robert G. Wilson v_, Nov 07 2005