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

Author

Eric W. Weisstein, Aug 26 2010

Keywords

• nonn
• cons

Comments

No closed form is known.

Examples

			0.14057701495515371558...
		

Formula

(1 - (192*Sum_{n=1..infinity} (tanh(((-1 + 2*n)*Pi)/2)/(-1 + 2*n)^5))/Pi^5)/3.