%I M2211 #18 May 08 2018 15:11:54

%S 1,1,1,1,3,1,1,15,1,5,21,5,1,21,1,1,231,5,1,1365,1,55,21,1,1,663,11,5,

%T 57,5,1,15015,1,17,483,1,11,25935,1,5,21,935,1,7917,1,23,19437,5,1,

%U 3315,1,55,21,1,1,191919,253,2465,21,5,1,1734915,1,1,17157,17,1

%N Denominator of (2n+1)(2n+2) B_{2n}, where B_n are the Bernoulli numbers. Also denominators of the asymptotic expansion of the polygamma function psi'''(z).

%D M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 260, (6.4.14).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Vincenzo Librandi, <a href="/A006956/b006956.txt">Table of n, a(n) for n = 3..1000</a>

%H M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

%H M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 260, (6.4.14).

%t Join[{1, 1}, Table[Denominator[(4 n^2 + 6 n + 2) BernoulliB[2 n]], {n, 1, 70}]] (* _Vincenzo Librandi_, Aug 02 2013 *)

%Y Numerators are in A076549. Cf. A006955/A002427.

%K nonn,frac

%O 3,5

%A _Simon Plouffe_

%E More terms from _Ralf Stephan_, Oct 19 2002