A255006 a(n) is the numerator of polygamma(2n+1, 1) / Pi^(2n+2).

1, 1, 8, 8, 128, 176896, 2048, 3703808, 1437433856, 11443306496, 40728264704, 123922856542208, 5519125250048, 56921405366730752, 231279728174802403328, 258681888643685023744, 325620148558310146048, 113023230705723814256110993408

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. A255007 (denominators).

Programs

Mathematica

a[n_] := PolyGamma[2n+1, 1] / Pi^(2n+2) // Numerator; Table[a[n], {n, 0, 20}]