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A140244
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Decimal expansion of arccos(-1/4).
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12
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1, 8, 2, 3, 4, 7, 6, 5, 8, 1, 9, 3, 6, 9, 7, 5, 2, 7, 2, 7, 1, 6, 9, 7, 9, 1, 2, 8, 6, 3, 3, 4, 6, 2, 4, 1, 4, 3, 5, 0, 7, 7, 8, 4, 3, 2, 7, 8, 4, 3, 9, 1, 1, 0, 4, 1, 2, 1, 3, 9, 6, 0, 7, 4, 8, 9, 4, 4, 8, 3, 2, 6, 3, 6, 2, 4, 1, 2, 5, 7, 2, 1, 7, 2, 5, 7, 6, 6, 1, 5, 4, 8, 9, 9, 0, 7, 3, 1, 3, 5, 5, 9, 6, 1, 6
(list; constant; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Angle in radians of the obtuse angle of the obtuse scalene triangle with sides of lengths 2, 3 and 4, the scalene triangle with least integer side lengths.
A140240 + A140242 + A140244 = arccos(7/8) + arccos(11/16) + arccos(-1/4) = Pi.
Arccos(-1/4) is the least positive x for which the function f(x)=cos(x)+cos(2x) attains its minimum value, which is -9/8. [From Clark Kimberling, Oct 28 2011]
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FORMULA
| arccos(-1/4) = Pi - arcsin(sqrt(15)/4) = Pi - arctan(sqrt(15)).
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EXAMPLE
| 1.82347658193697527271697912863346241435077843278439110412139607489448326362...
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PROG
| (PARI) acos(-1/4)
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CROSSREFS
| Cf. A140239, A140240, A140241, A140242, A140243, A140245, A140246, A140247, A140248, A140249.
Sequence in context: A185111 A086058 A013662 * A160105 A167162 A096257
Adjacent sequences: A140241 A140242 A140243 * A140245 A140246 A140247
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KEYWORD
| cons,nonn
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AUTHOR
| Rick L. Shepherd (rshepherd2(AT)hotmail.com), May 14 2008
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