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 A063248 #7 Jul 02 2025 20:00:53
%S A063248 4,9,407,25,9,49,893,1387,15,121,23533,169,21,4717,10579,289,27,361,
%T A063248 25,49,33,529,32437,61903,39,24523,35,841,45,961,39917,77,51,64993,
%U A063248 111277,1369,57,91,99101,1681,49,1849,55,108389,69,2209,207133,139163
%N A063248 Smallest composite number in base n which contains its largest proper factor as a substring.
%t A063248 sublist[ s_, l_ ] := Module[ {i, ls=Length[ s ]}, For[ i=1, i+ls-1<=Length[ l ], i++, If[ s==Take[ l, {i, i+ls-1} ], Return[ True ] ] ]; False ]; a[ n_ ] := Module[ {k}, For[ k=4, True, k++, If[ !PrimeQ[ k ]&&sublist[ IntegerDigits[ Divisors[ k ][ [ -2 ] ], n ], IntegerDigits[ k, n ] ], Return[ k ] ] ] ];
%Y A063248 Cf. A062238.
%K A063248 base,nonn
%O A063248 2,1
%A A063248 _Robert G. Wilson v_, Aug 08 2001
%E A063248 More terms from _Dean Hickerson_, Aug 10 2001