Connecting LEDs in series-parallel like the ASCII schem below is okay? I don't see any reason why it shouldn't work. If a lot of LEDs, like the 7 below, are paralleled, the total current for each parallel string should be an average, i.e. some LEDs will draw more, some less, so they should average out. So the diff between the two strings should be minimal. But if one parallel string draws a few more milliamps, the V drop will be less for this string, and more for the other string. But this diff should also be minimal.
The reason for this configuration is that the PC board is laid out for ICs, and this connection pattern is more convenient, with less trace cutting and jumpering.
Typical resistors are 51 ohms, 3.5V across each white LED, about 9.6V for LED current of 30 mA each.
View with Courier Font
+V | +----+----+---------+--- - - | | | \ \ \ / / / Resistors \ \ \ / / / | | | 7 total _|_ _|_ _|_ \ /-> \ /-> \ /->--- --- --- LEDs | | | | | | +----+----+---------+--- - - | | +----+----+---------+--- - - | | | \ \ \ / / / Resistors \ \ \ / / / | | | 7 total _|_ _|_ _|_ \ /-> \ /-> \ /->
--- --- --- LEDs | | | | | | +----+----+---------+--- - - | -V