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From higher-order Bernoulli numbers: denominator of the D-number D2n(2n-1).
3

%I #17 Jul 02 2019 14:13:28

%S 3,5,21,45,11,1365,45,51,399,3465,345,20475,189,145,7161,58905,105,

%T 27417,117,6765,148995,108675,329,2436525,65637,26235,21945,4959,177,

%U 85180095,135135,60775,1650411,108675

%N From higher-order Bernoulli numbers: denominator of the D-number D2n(2n-1).

%H Gheorghe Coserea, <a href="/A261272/b261272.txt">Table of n, a(n) for n = 1..200</a>

%H Guodong Liu, <a href="http://dx.doi.org/10.1155/2009/605313">A Recurrence Formula for D Numbers D2n(2n-1)</a>, Discrete Dynamics in Nature and Society, Volume 2009 (2009).

%H N. E. Nørlund, <a href="http://gdz.sub.uni-goettingen.de/dms/load/img/?IDDOC=237538">Vorlesungen über Differenzenrechnung</a> Springer 1924, p. 463.

%H <a href="/index/Be#Bernoulli">Index entries for sequences related to Bernoulli numbers.</a>

%t NorlundD[nu_, n_] := (-2)^nu NorlundB[nu, n, n/2];

%t Table[NorlundD[2n, 2n-1] // Denominator, {n, 1, 34}] (* _Jean-François Alcover_, Jul 02 2019 *)

%o (PARI) x='x+O('x^66); apply(denominator, select(i->i, Vec(-1 + serlaplace((x / log(x + sqrt(1+x^2)))^2 / sqrt(1+x^2)))))

%Y Cf. A001905.

%K nonn,frac

%O 1,1

%A _Gheorghe Coserea_, Aug 13 2015