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Calculation of the Pyramid. (Sequence of numerical progressions)
A. Werner, Front side: Progressive sums:-1,-2,-3,-4,-5... 1,2,3,4,5... We express the formulas: Sn= (a₁n²+n)/2, ; Sn-1=(a₁n²-n)/2 ("n" is the number of summable terms, and "a₁" is the first term of the progression.) For negative or positive values of "n", the expressions....
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Королёв Александр, 2017-06-17
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Морозов Виктор, 2017-06-06