A063395 - OEIS

%I #10 Jul 29 2020 08:39:31

%S 1,3,19,131,979,7683,62099,511619,4271699,36018179,305998099,

%T 2615234691,22459983059,193665818115,1675580699539,14538892408451,

%U 126467748738899,1102484411211779,9629327766561299,84247346901823619,738200425192338899,6477139329614712323

%N T(2n,n) with T(n,m) as in A063394.

%F G.f.: 4x/sqrt(1-10x+9x^2) + (1-2x)/(1-x). - _Ralf Stephan_, Mar 23 2004

%F Conjecture: (-n+1)*a(n) +(11*n-17)*a(n-1) +(-19*n+43)*a(n-2) +9*(n-3)*a(n-3)=0. - _R. J. Mathar_, Jun 10 2013

%o (PARI) m=matrix(50,50):for(i=1,50,m[1,i]=1:m[i,1]=1):for(i=2,50, for(k=1,i,x=i-k+1: if(m[x,k]==0,m[x,k]=sum(n=2,k-1,m[x,n])+sum(n=2,x-1,m[n,k])+k+x-1))):for(n=1,24,print1(m[n,n]",")) /* _Ralf Stephan_ */

%Y Equals 4*A084771(n-1) - 1, n>0.

%K nonn

%O 0,2

%A _Floor van Lamoen_, Jul 16 2001

%E More terms from _Ralf Stephan_, Mar 23 2004