cp's OEIS Frontend

A128413 Inverse of number triangle A128412.

%I A128413 #2 Mar 30 2012 18:59:20
%S A128413 1,2,1,12,8,1,80,60,12,1,560,448,112,16,1,4032,3360,960,180,20,1,
%T A128413 29568,25344,7920,1760,264,24,1,219648,192192,64064,16016,2912,364,28,
%U A128413 1,1647360,1464320,512512,139776,29120,4480,480,32,1,12446720
%N A128413 Inverse of number triangle A128412.
%C A128413 First column is A069723.
%F A128413 Number triangle T(n,k)=if(k=0,2^n*(C(2n,n)/2+0^n/2),2^(n-k)*C(2n,n-k)); Column k has g.f. if(k=0,4x/(sqrt(1-8x)(1-sqrt(1-8x))),(1/sqrt(1-8x))*((1-4x-sqrt(1-8x))/(8x))^k);
%e A128413 Triangle begins
%e A128413 1,
%e A128413 2, 1,
%e A128413 12, 8, 1,
%e A128413 80, 60, 12, 1,
%e A128413 560, 448, 112, 16, 1,
%e A128413 4032, 3360, 960, 180, 20, 1,
%e A128413 29568, 25344, 7920, 1760, 264, 24, 1,
%e A128413 219648, 192192, 64064, 16016, 2912, 364, 28, 1
%Y A128413 Cf. A128417.
%K A128413 easy,nonn,tabl
%O A128413 0,2
%A A128413 _Paul Barry_, Mar 02 2007