|
%I #12 Jan 03 2018 15:55:45
%S 1,1,3,3,15,45,315,315,2835,14175,155925,467775,6081075,42567525,
%T 58046625,638512875,10854718875,97692469875,1856156927625,
%U 9280784638125,194896477400625,2143861251406875,49308808782358125,147926426347074375,217538862275109375,4370553505709015625
%N Denominator of l(n), where l(1)=1, l(2)=2, l(n)=l(n-1)+2*l(n-2)/n.
%D Szekeres, G. The average value of skew Hadamard matrices. Proceedings of the First Australian Conference on Combinatorial Mathematics (Univ. Newcastle, Newcastle, 1972), pp. 55--59. Univ. of Newcastle Res. Associates, Newcastle, 1972. MR0349708 (50 #2201)
%H G. C. Greubel, <a href="/A209430/b209430.txt">Table of n, a(n) for n = 1..500</a>
%e 1, 2, 8/3, 11/3, 71/15, 268/45, 2302/315, 2771/315, 29543/2835, 172654/14175, 2194624/155925, 7533469/467775, 111102841/6081075, 875654984/42567525, ...
%t Denominator[RecurrenceTable[{a[1]==1,a[2]==2,a[n]==a[n-1]+(2a[n-2])/n},a,{n,30}]] (* _Harvey P. Dale_, Mar 30 2014 *)
%Y Cf. A209429, A052127.
%K nonn,frac
%O 1,3
%A _N. J. A. Sloane_, Mar 22 2012
|
