A180309 Decimal expansion of the torsional rigidity constant for a square shaft.

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.

Links

Table of n, a(n) for n=0..93.

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

Adjacent sequences: A180306 A180307 A180308 * A180310 A180311 A180312

Keyword

nonn,cons

Author

Eric W. Weisstein, Aug 26 2010

Status

approved