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A180309
Decimal expansion of the torsional rigidity constant for a square shaft.
2
1, 4, 0, 5, 7, 7, 0, 1, 4, 9, 5, 5, 1, 5, 3, 7, 1, 5, 5, 8, 8, 4, 6, 8, 7, 3, 0, 7, 5, 2, 8, 6, 1, 2, 9, 6, 8, 4, 9, 7, 4, 8, 2, 4, 6, 4, 7, 0, 3, 5, 5, 9, 6, 4, 5, 9, 0, 9, 9, 7, 0, 3, 5, 4, 9, 7, 9, 4, 4, 6, 0, 3, 1, 9, 7, 3, 2, 7, 5, 1, 0, 2, 1, 1, 8, 5, 3, 8, 9, 3, 7, 3, 3, 3
OFFSET
0,2
COMMENTS
No closed form is known.
FORMULA
(1 - (192*Sum_{n=1..infinity} (tanh(((-1 + 2*n)*Pi)/2)/(-1 + 2*n)^5))/Pi^5)/3.
EXAMPLE
0.14057701495515371558...
CROSSREFS
Sequence in context: A153018 A102913 A197509 * A102293 A198747 A021965
KEYWORD
nonn,cons
AUTHOR
Eric W. Weisstein, Aug 26 2010
STATUS
approved