%I A008957
%S A008957 1,1,1,1,5,1,1,14,21,1,1,30,147,85,1,1,55,627,1408,341,1,1,91,2002,
%T A008957 11440,13013,1365,1,1,140,5278,61490,196053,118482,5461,1,1,204,12138,
%U A008957 251498,1733303,3255330,1071799,21845,1,1,285,25194,846260,10787231
%N A008957 Triangle of central factorial numbers T(2n,2n-2k), k >= 0, n >= 1 (in 
               Riordan's notation).
%D A008957 D. Dumont, Interpretations combinatoires des nombres de Genocchi, Duke 
               Math. J., 41 (1974), 305-318.
%D A008957 J. Riordan, Combinatorial Identities, Wiley, 1968, p. 217, Table 6.2(a).
%D A008957 R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see 
               Problem 5.8.
%F A008957 There is a simple recurrence.
%e A008957 1; 1,1; 1,5,1; 1,14,21,1; 1,30,147,85,1; ...
%p A008957 A036969 := proc(n,k) local j; 2*add(j^(2*n)*(-1)^(k-j)/((k-j)!*(k+j)!),
               j=1..k); end; # Gives rows of triangle in reversed order
%Y A008957 Essentially same as A036969. Cf. A008955.
%Y A008957 Sequence in context: A111910 A144438 A157207 this_sequence A136267 A109960 
               A056940
%Y A008957 Adjacent sequences: A008954 A008955 A008956 this_sequence A008958 A008959 
               A008960
%K A008957 nonn,nice,easy,tabl
%O A008957 1,5
%A A008957 N. J. A. Sloane (njas(AT)research.att.com).
%E A008957 More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 16 2000