A117270 Matrix log of triangle M = A117269, which satisfies: M - (M-I)^2 = C where C is Pascal's triangle.
0, 1, 0, 2, 2, 0, 12, 6, 3, 0, 134, 48, 12, 4, 0, 2100, 670, 120, 20, 5, 0, 42302, 12600, 2010, 240, 30, 6, 0, 1041852, 296114, 44100, 4690, 420, 42, 7, 0, 30331814, 8334816, 1184456, 117600, 9380, 672, 56, 8, 0, 1019056260, 272986326, 37506672, 3553368
Offset: 0
Examples
Triangle begins: 0; 1,0; 2,2,0; 12,6,3,0; 134,48,12,4,0; 2100,670,120,20,5,0; 42302,12600,2010,240,30,6,0; 1041852,296114,44100,4690,420,42,7,0; ...
Programs
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PARI
{a(n)=local(C=matrix(n+1,n+1,r,c,if(r>=c,binomial(r-1,c-1))),M=C,L); for(i=1,n+1,M=(M-M^0)^2+C);L=sum(r=1,#M,-(M^0-M)^r/r);return(L[n+1,1])}
Formula
T(n,k) = A117271(n-k)*C(n,k).
Comments