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A224802
Column 2 of triangle A224798.
4
1, 4, 16, 192, 2816, 84992, 3223552, 247250944, 23344644096, 4762175799296, 1120173091192832, 644677614732050432, 378488143248684482560, 653528083344895592366080, 949029769901509397631205376, 5192644934824847025023714590720
OFFSET
0,2
PROG
(PARI) {A224798(n, k)=if(n<k|k<0, 0, if(n==k, 1, if(n==k+1, 2^(n-1), sum(j=k+1, n, A224798(n, j)*A224798(j, k+1) ))))}
{a(n)=A224798(n+2, 2)}
for(n=0, 15, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Apr 22 2013
STATUS
approved