>From RE Boss's blog http://www.jsoftware.com/jwiki/RE%20Boss/J-blog/HN and this essay
http://www.jsoftware.com/jwiki/Essays/Hamming%20Number There are a few approaches mentioned to either directly get the ith hamming number or generate the list. an issue with nh (super fast) is that it is innacurate.) nh 1001 52428800 {: hn21b 1002 NB. Roger's version 52428800 Another function approach that is very fast, and doesn't limit it to the hamming factors 2 3 5 is to get a list of hamming numbers below a threshold: X =: 1 : 'm&{::@:[' H =: (0 X ([: ~. ] #~ >:) 1 X (] , [: , */) ])(^:_)&1 # H 52428800 ; 2 3 5 1002 {: /:~ H 52428800 ; 2 3 5 52428800 Can also apply to aribtrary prime list (Roger's function is also easily modified to do this) # H 52428800 ; 2 3 5 7 11 13 13102 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
