Search: id:A095922 Results 1-1 of 1 results found. %I A095922 %S A095922 1,0,1,0,3,1,15,15,105,190,945,2410,10263,31890,127699,444458,1751685, %T A095922 6518736,25807445,100152288,401449271,1602902055,6519160851,26580508625, %U A095922 109656966853,454524861846,1899821492925,7982263725826,33757439931675 %N A095922 Dimension of invariants of n-th tensor power of 5-dimensional irreducible representation of B_2. %C A095922 The analogous sequence for G_2 is A059710. %D A095922 Alec Mihailovs, A Combinatorial Approach to Representations of Lie Groups and Algebras, Springer-Verlag New York (2004). %F A095922 a(n) =sum(A000108(i)*A000108(i+1)*binomial(n, 2*i), i=0..floor(n/2)) - sum(A000108(i)^2*binomial(n, 2*i-1), i=0..floor((n+1)/2)); exponential generating function = exp(t)*b(t) where b(t) is the exponential generating function of the sequence B(n) = (-1)^n*A000108(floor((n+1)/2))*A000108(floor(n/ 2+1)). %F A095922 a(0)=1, a(1)=0, a(2)=1 and (n+3)(n+4)a(n)=3(n-1)(n+2)a(n-1)+(n-1)(13n+4)a(n-2)-15(n-1)(n-2)a(n-3) for n>2. %e A095922 a(2)=1 because SO(5) has unique (up to multiplication by a constant) invariant in V\otimes V - the quadratic form x^2+y^2+z^2+u^2+v^2. %p A095922 ca:=n->binomial(n+n,n)/(n+1); a:=n->add(ca(i)*ca(i+1)*binomial(n,2*i), i=0..floor(n/2))- add(ca(i)^2*binomial(n,2*i-1),i=0..floor((n+1)/ 2)); seq(a(n),n=0..40); %p A095922 A095922:=rsolve({(n+3)*(n+4)*A(n)=3*(n-1)*(n+2)*A(n-1)+(n-1)*(13*n+4)*A(n-2)-15*(n-1)*(n-2)*A(n-3), A(0)=1,A(1)=0,A(2)=1},A(n),makeproc); %Y A095922 Cf. A000108, A059710. %Y A095922 Sequence in context: A144006 A113378 A156289 this_sequence A089278 A087071 A053485 %Y A095922 Adjacent sequences: A095919 A095920 A095921 this_sequence A095923 A095924 A095925 %K A095922 easy,nice,nonn %O A095922 0,5 %A A095922 Alec Mihailovs (alec(AT)mihailovs.com), Jul 11 2004 Search completed in 0.001 seconds