A255007 a(n) is the denominator of polygamma(2n+1, 1) / Pi^(2n+2).

6, 15, 63, 15, 33, 4095, 3, 255, 3591, 825, 69, 4095, 3, 435, 21483, 255, 3, 8636355, 3, 33825, 18963, 345, 141, 69615, 33, 795, 10773, 435, 177, 425900475, 3, 255, 97083, 15, 2343, 630453915, 3, 15, 4977, 575025, 249

Offset: 0

Author

Jean-François Alcover, Feb 12 2015

Keywords

• nonn
• frac
• easy

Examples

			Polygamma values {Pi^2/6, Pi^4/15, 8*Pi^6/63, 8*Pi^8/15, 128*Pi^10/33, ...} give numerators {1, 1, 8, 8, 128, ...} and denominators {6, 15, 63, 15, 33, ...}.
		

Links

• Eric Weisstein's MathWorld, Polygamma Function.
• Wikipedia, Polygamma Function.

Crossrefs

Cf. A255006 (numerators).

Programs

Mathematica

a[n_] := PolyGamma[2n+1, 1] / Pi^(2n+2) // Denominator; Table[a[n], {n, 0, 40}]