The number of size-x subsets of y objects (number of equal sized subsets) is:
ness=: 4 : 0 " 0 (!y) % (!x) * (!y%x)^x ) 2x ness 2x*>:i.10 1 3 10 35 126 462 1716 6435 24310 92378 http://www.research.att.com/~njas/sequences/A001700 3x ness 3x*>:i.8 1 15 280 5775 126126 2858856 66512160 1577585295 http://www.research.att.com/~njas/sequences/A060542 4x ness 4x*>:i.8 1 105 15400 2627625 488864376 96197645544 19688264481600 4148378852099625 http://www.research.att.com/~njas/sequences/A082368 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
