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First numerator and then denominator of central elements of Leibniz's Harmonic Triangle.
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%I #14 Jan 02 2022 17:11:18

%S 1,1,1,6,1,30,1,140,1,630,1,2772,1,12012,1,51480,1,218790,1,923780,1,

%T 3879876,1,16224936,1,67603900,1,280816200,1,1163381400,1,4808643120,

%U 1,19835652870,1,81676217700,1,335780006100,1,1378465288200,1

%N First numerator and then denominator of central elements of Leibniz's Harmonic Triangle.

%D L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 83, Problem 25.

%F a(2n+1) = A056040(2n+1) = A100071(2n+1). - _M. F. Hasler_, Jan 25 2012

%Y Cf. A003506.

%Y Cf. A002457.

%K nonn,easy

%O 1,4

%A _Mohammad K. Azarian_

%E More terms from _James A. Sellers_, Dec 13 1999