...always under very slow construction.
If you need a non-standard resistor value you could probably realize a close match using two resistor. If you use two resistor in series it is quite easy to figure out which values give the best match; on the other hand, using a parallel connection it is not so easy (at least for me) to find a good combination. This tool shows which combinations of two resistor (series or parallel) gives a match better than the closest standard value, for the E12 and E24 series (the E12 series goes like 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82..., while the E24 add the values in-between - 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91...).