MentalGrind
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May be a Simple Series Puzzle !
MentalGrind replied to Commander's topic in Brain Teasers and Puzzles
0, 7, 28, 69, 136, 235 Simple enough, took me just 15 mins.... f(n) = (x-1)(x2+2x-1) f(1) = (1-1)(1+2-1) = 0 f(2) = (2-1)(4+4-1) = 7 f(3) = (3-1)(9+6-1) = 28 f(4) = (4-1)(16+8-1) = 69 f(5) = (5-1)(25+10-1) = 136 f(6) = (6-1)(36+12-1) = 235 . . . best, Anita