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A216542
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Decimal expansion of Sum_{k=1..50000} (-1)^(k-1)/(2k-1).
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10
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7, 8, 5, 3, 9, 3, 1, 6, 3, 3, 9, 7, 4, 4, 8, 8, 0, 9, 6, 1, 5, 6, 6, 0, 5, 9, 5, 8, 1, 9, 8, 7, 6, 0, 2, 6, 0, 4, 9, 2, 9, 1, 6, 5, 7, 3, 4, 3, 7, 7, 8, 9, 8, 1, 2, 9, 3, 7, 2, 2, 6, 3, 4, 2, 5, 2, 0, 5, 3, 7, 8, 2, 0, 6, 1, 0, 8, 2, 6, 7, 4, 0, 6, 1, 7, 8, 3, 1, 0, 4, 5, 2, 7, 5, 4, 8, 6, 7, 6, 3, 4, 4, 2, 1, 8, 1, 6, 3, 7, 1, 2, 5, 4, 6, 8, 5, 2, 4, 1, 2, 5, 3, 0, 9, 6
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OFFSET
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0,1
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COMMENTS
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A deceptively correct-looking approximation to Pi/4.
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LINKS
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FORMULA
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EXAMPLE
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Pi/4: 0.785398163397448309615660845819875721049292349843776455...
This sum: 0.785393163397448809615660595819876026049291657343778981...
..........=================^========^^======^^=^=====^^^^^====^^^^...
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MAPLE
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Digits:=300; M:=50000; add(evalf((-1)^(k-1)/(2*k-1)), k=1..M);
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MATHEMATICA
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First[RealDigits[Sum[(-1)^(k-1)/(2*k-1), {k, 50000}], 10, 100]] (* Paolo Xausa, Apr 23 2024 *)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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