$ bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
ibase=16
30
48
ibase=A
48 + 19
67
obase = 16
67
43

えーと 0x43 は 'C'
が13番目の添字に...