Efficient algorithm for conversion between numeral system

Question

Is there any efficient algorithm for conversion between numeral system when the size of source integer is arbitrary?

For example, assume that there is an integer array {1, 4, 8} which is 148 in decimal format as an input. It might be converted to {9, 4} in hexadecimal format, or {2, 2, 4} in octal, or {1, 0, 0, 1, 0, 1, 0, 0} in binary format, or just {148} in 1234-ary format or something.

It's simple when the actual value can be expressed in word-size supported by machine. But when it goes to arbitrary size, I cannot find efficient way better than O(n^2).

Answer 1

Divide by the base, push back the module, rinse and repeat while quotient != 0.

So, for example convert 148 in base 16

148 / 16 = 9 r 4
  9 / 16 = 0 r 9

So, 148 in hex is 0x94. This shouldn't take so long.