A155896 - OEIS

%I #2 Mar 31 2012 13:48:25

%S 1,2,5,4,8,3,9,26,52,18,25,10,33,53,32,15,13,20,30,5,17,42,7,4,23,43,

%T 78,50,28,113,8,44,19,334,59,100,195,27,22,14,91,172,371,16,93,9,12,

%U 102,66,26,46,95,279,303,69,331,272,52,286,79,264,298,18,21,190,104,47,138,255

%N Least positive integer such that a(n)! starts with n, both written in base 6.

%e a(3) = 5 since 5!=120 is the least factorial to start with digit "3" when written in base 6. a(8) = 26 since 8 = 12[6] (i.e. written in base 6) and 26! is the smallest factorial to start with digits "12" when written in base 6.

%o (PARI) A155896(n)={ local( F=1,k=1 ); while( F\1!=n, F*=k++; while( F>=n+1, F/=6)); k}

%Y Cf. A155891--A155894, A018799, A076219.

%K base,nonn

%O 1,2

%A _M. F. Hasler_, Feb 01 2009