There isn't a seed. All he's done is used MCedit or world edit to remove the blocks, then built up from bedrock to his required height before removing the bedrock. And there you go, skyblock ready to play.
123 USA pretty flat good seed to play on
The Pokemon 123 in leaf green is scyther, i think you can get it by trading it from fire red...
go around mt. pyre from route 121 when you get to the other side your on route 123
123
123
the cylinder numbering on the block is 135 246
109 in the King James version and 123 in the New International version.
123*#0000#11
Sesame Street 123 - 1988 VG was released on: USA: 1988 (NES version)
123
Telecom call *123 and ask them Vodafone call 0124 before the number
123
123 USA pretty flat good seed to play on
Someone in California
123. using this for my report
a Ford Taurus
123