Ruby 2.0

[Mauricio Fernández]

Small one: (two more chars)

a=[];10.times{|n|a<<1;puts"
"*(9-n)*3+"%6d"*-~n%a;n.times{|i|a[n]+=a[n-=1]}}

Another obvious one:

a=[];10.times{|n|a<<1;puts" "*(9-n)*3+"%6d"*-~n%a;n.times{a[n]+=a[n-=1]}}

(|i|) DUH
We're down to 73 now.