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 A155895 #2 Mar 31 2012 13:48:25
%S A155895 1,2,17,4,6,3,29,7,10,19,31,8,18,14,37,61,81,17,33,11,63,94,9,4,13,24,
%T A155895 16,6,27,22,52,152,28,21,143,45,35,29,67,7,62,15,247,181,193,10,105,
%U A155895 48,12,97,19,167,36,72,146,75,31,391,69,40,186,486,133,8,57,46,18,103,115
%N A155895 Least positive integer such that a(n)! starts with n, both written in base 5.
%e A155895 a(3) = 17 since 17! is the least factorial to start with digit "3" when written in base 5. a(5) = 6 since 5 = 10[5] (i.e. written in base 5) and 6! = 720 = 625 + 75 + 20 = 10340[5] is the smallest factorial to start with digits "10" when written in base 5.
%o A155895 (PARI) A155895(n)={ local( F=1,k=1 ); while( F\1!=n, F*=k++; while( F>=n+1, F/=5)); k}
%Y A155895 Cf. A155891--A155894, A018799, A076219.
%K A155895 base,nonn
%O A155895 1,2
%A A155895 _M. F. Hasler_, Feb 01 2009