%I A024283
%S A024283 0,1,8,136,3968,176896,11184128,951878656,104932671488,14544442556416,
%T A024283 2475749026562048,507711943253426176,123460740095103991808,
%U A024283 35125800801971979943936,11559592093904798920736768
%N A024283 Expansion of tan(x)^2/2.
%C A024283 Number of cyclically reverse alternating permutations of length 2n+1, 
               cf. A024255. - Vladeta Jovovic (vladeta(AT)eunet.rs), May 20 2007
%D A024283 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 259, T(n,2).
%e A024283 (tan x)^2 = x^2 + 2/3*x^4 + 17/45*x^6 + 62/315*x^8 + ...
%t A024283 Tan[ x ]^2/2 (* Even Part *)
%Y A024283 A009764.
%Y A024283 Cf. A009764, A000182. A diagonal of A059419.
%Y A024283 Sequence in context: A132869 A036915 A049211 this_sequence A134053 A136472 
               A145404
%Y A024283 Adjacent sequences: A024280 A024281 A024282 this_sequence A024284 A024285 
               A024286
%K A024283 nonn,easy
%O A024283 0,3
%A A024283 R. H. Hardin (rhhardin(AT)att.net)
%E A024283 Extended and signs tested 03/97.