What do the parenthesized numbers in the [color] Scenes mean? As you can see at the top of this answer, the [color] Scenes (Black Scene, Red Scene, etc.) in the Monogatari series all include a parenthesized number beneath the romanized form of the name of the color shown. 

Here's a list of them:

ROMANIZED  GLOSS         NUMBER   KANJI(READING)
aka        "red"          (135)   赤　（あか） 
kuro       "black"        (629)   黒　（くろ）
shiro      "white"       (4646)   白　（しろ）
ki         "yellow"      (0303)   黄　（き）
ouchi      "lilac"        (349)   楝　（おうち）
ao         "blue"         (014)   青　（あお）
momo       "peach"        (372)   桃　（もも）
moegi      "light green"  (469)   萌黄（もえぎ）
murasaki   "purple"       (039)   紫　（むらさき）


Question: What do the numbers mean?

Possibilities:


Something to do with color codes (but this is unlikely because neither "white" nor "black" seems to have a special number)
Some sort of character code for either the kanji, the kana reading, or the romanized form (though I haven't come up with anything for this)
It's all a clever ruse by Shinbo to confuse us
???
Most colors can be found in one form or another in image search results from Google (query color 8888). They seem to correspond to knitting yarn color codes. Some colors are in DMC chart, I couldn't find out where others are from.