A144631 Second diagonal (or column) of A144630.

4, 12, 880, 46900, 1615824, 45094896, 1115345088, 25519125060, 553014576400, 11514200107696, 232490008680384, 4581732884262352, 88532684825838400, 1683073282734360000, 31561148509363526400, 584964180982546208100

Offset: 2

Author

Daniel McLaury and Ben Golub, Jan 20 2009

Keywords

• nonn

Links

• Klaus Brockhaus, Table of n, a(n) for n=2..100

Programs

Magma

[ [ &+[I[i][j]: i, j in [k..n] ]: k in [n..1 by -1] ][2] where I:=H^-1 where H:=Matrix(Rationals(), n, n, [ < i, j, 1/(i+j-1) >: i, j in [1..n] ] ): n in [2..17] ]; // Klaus Brockhaus, Jan 22 2009

Maple

invH := proc(n,i,j) (-1)^(i+j)*(i+j-1)*binomial(n+i-1,n-j)*binomial(n+j-1,n-i)* (binomial(i+j-2,i-1))^2 ; end: A144630 := proc(n,k) local T,i,j ; T := 0 ; for i from n-k+1 to n do for j from n-k+1 to n do T := T+invH(n,i,j) ; od; od; RETURN(T) ; end: A144631 := proc(n) A144630(n+1,2) ; end: for n from 1 to 20 do printf("%a,",A144631(n)) : od: # R. J. Mathar, Jan 21 2009

Extensions

More terms from R. J. Mathar and Klaus Brockhaus, Jan 21 2009