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Sum

What is
$$\sum_{i=1}^{\infty}\frac{1}{i 2^i}$$
?

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cube numbers parabolas circles hexagons tiling mean the only crossnumber quadratics surds balancing differentiation means books ave doubling ellipses triangles dominos complex numbers integration games scales crossnumber indices routes numbers 2d shapes speed remainders polygons cryptic clues christmas square roots perfect numbers coordinates time area chess money star numbers multiplication advent number digits algebra 3d shapes rugby grids people maths sums planes floors multiples proportion division sport triangle numbers addition rectangles dodecagons squares median clocks sum to infinity wordplay symmetry cryptic crossnumbers products arrows palindromes fractions crossnumbers odd numbers colouring dates crosswords bases probability logic factors irreducible numbers trigonometry chocolate unit fractions taxicab geometry shape folding tube maps volume shapes averages graphs regular shapes menace spheres square numbers dice angles functions elections integers partitions probabilty calculus perimeter gerrymandering lines cards sequences chalkdust crossnumber prime numbers coins digital clocks percentages factorials range geometry pascal's triangle

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