A393300 - OEIS

%I #11 Feb 17 2026 20:55:11

%S 0,5,7,17,21,36,61,73,82,87,89,97,136,151,166,196,201,260,389,491,514,

%T 515,591,640,682,703,713,717,722,741,791,798,853,869,883,913,928,934,

%U 978,979,982,1003,1025,1296,1474,1619,2014,2257,2416,2716,2954,3027,3257

%N a(1) = 0; for n > 1, a(n) is the smallest unused number k such that k! contains a(1), a(2), ..., a(n-1) as substrings.

%H Scott R. Shannon, <a href="/A393300/b393300.txt">Table of n, a(n) for n = 1..190</a>

%F a(n) > a(n-1).

%e a(5) = 21 as 21! = 51090942171709440000 which contains a(1) = 0, a(2) = 5, a(3) = 7, a(4) = 17 as substrings.

%Y Cf. A000142, A393301, A385673, A346120, A392010, A392011.

%K nonn,base

%O 1,2

%A _Scott R. Shannon_, Feb 10 2026