OFFSET
2,1
LINKS
Klaus Brockhaus, Table of n, a(n) for n=2..100
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
PROG
(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
CROSSREFS
KEYWORD
nonn
AUTHOR
Daniel McLaury and Ben Golub, Jan 20 2009
EXTENSIONS
More terms from R. J. Mathar and Klaus Brockhaus, Jan 21 2009
STATUS
approved