2,3,4,15,16,__       ( a)19 (b)20 (c)24 (d)224 (e)255?
477491
I say (e)255.\n\n2   = 2^1 [or 2^(2^0)]\n3   = 2^2 - 1\n4   = 2^2 [or 2^(2^1)]\n15  = 2^4 - 1\n16  = 2^4 [or 2^(2^2)]\n255 = 2^8 - 1 \n256 = 2^8 [or 2^(2^3)]
907310
5\n\n1s,2s,2px,2py,2pz
149171
1,365\n\nor 15!/(11! * 4!)\n\nie n!/[k! * (n-k)!]
465985
1 - D\n2 - B\n3 - C\n4 - C
695512
Answers choices are:\n     1, 4, 3, 2, 2,\n      3, 1, 4, 2, 1,\n      1, 1, 4, 2, 1\n      3, 2, 3, 4, 1\n      3, 4, 1, 2, 4
804536
1 + 7 + 7(6) + 42(5) + 210(4) + 840(3) + 2520(2) + 5040(1) = 13,700
316451
the numbers are \n 2+6+18= 26\n 2*6*18= 216
771168
1= B\n2= A\n3= D\n4= D\n5= D\n6= C
376218
Not sure how many you need, but here are the first few:\n2,3,5,7,11,13,17,19,23,29,31, 37,41,43,47,53,59,61,67, 71,73,79,83,89,97,101
555500
here are the answers:\n-17x-19 for the first one \n22x+1 for the second one\n-6x^2+3x+15 for the third one, which can also be written as -3(2x^2-x-5)
88384
1 * 1650\n2 * 825\n3 * 550\n5 * 330\n6 * 275\n10 * 165\n11 * 150\n15 * 110
971462
48=2(20+w)\n24=20+w\nw=4
1060907
-1, +4\n12, 11, 15, 14\n*18, 17, etc.
990622
if you know permutation/combination..the answer is easy to understand...\n\nlike 23C23+23C22+23C21+......+23C1
780226
lets take the common multiple 210\n15,35,21 and 2 are the factors\nI was thinking of 105 but only 15.35.21 come to my mind
840649
1.\nn | n + 20\n------------\n0 | 20\n1 | 21\n2 | 22\n3 | 23\n4 | 24\n\nn | 3n - 35\n-------------\n1 | -32 \n2 | -29 \n3 | -26 \n4 | -23
95089
1(1)+0(2)+1(4)+1(8)+1(16)+0(32)+0(64)+0(128)+1(256)=\n1+0+4+8+16+0+0+0+256=\n285