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A309091
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Decimal expansion of 4/(Pi-2).
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4
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3, 5, 0, 3, 8, 7, 6, 7, 8, 7, 7, 6, 8, 2, 1, 7, 3, 2, 2, 4, 0, 7, 8, 1, 9, 4, 0, 3, 0, 2, 2, 9, 0, 7, 7, 5, 8, 5, 0, 0, 7, 9, 6, 0, 1, 3, 6, 1, 1, 4, 8, 3, 1, 2, 7, 2, 8, 0, 9, 4, 1, 9, 0, 0, 2, 7, 9, 9, 6, 5, 7, 7, 4, 0, 8, 7, 4, 2, 1, 9, 9, 0, 2, 6, 9, 0, 3, 3, 5, 0, 3, 7, 6, 7, 0, 8, 9, 1, 4, 3, 9, 8, 2, 9, 1
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OFFSET
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1,1
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COMMENTS
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This can be computed using a recursion formula discovered by an algorithm called "The Ramanujan Machine":
1*3
4/(Pi-2) = 3 + --------------------
2*4
5 + ----------------
3*5
7 + ------------
4*6
9 + --------
11 + ... .
For a proof by humans see the arXiv:1907.00205 preprint linked below.
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LINKS
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EXAMPLE
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3.50387678776821732240781940302290775850079601361148312728094190...
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MAPLE
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nn:= 126: # number of digits
b:= i-> `if`(i<2*nn, 2*i+1 +i*(i+2)/b(i+1), 1):
evalf(b(1), nn);
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MATHEMATICA
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RealDigits[4/(Pi-2), 10, 120][[1]] (* Amiram Eldar, Jun 29 2023 *)
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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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