OFFSET
1,1
COMMENTS
Matrix square of the matrix B(n,m) = 2+3*(m-1), B containing the first terms of A016789
in its row n, n>0, 1<=m<=n.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10011 (rows 1 to 141, flattened)
FORMULA
T(n,m) = sum_{k=m..n} B(n,k)*B(k,m) = (3*m-1)*(3*m+3*n-2)*(n+1-m)/2.
Row sums: sum_{m=1..n} T(n,m) = A024212(n).
G.f. as triangle: x*y*(4+2*x+13*x*y-16*x^2*y+x^2*y^2-4*x^3*y^2)/((1-x)*(1-x*y))^3. - Robert Israel, May 06 2019
EXAMPLE
The matrix B starts as
2 ;
2,5 ;
2,5,8 ;
2,5,8,11 ;
2,5,8,11,14 ;
and interpreting this as a lower triangular matrix, its square T = B^2 starts
4;
14,25;
30,65,64;
52,120,152,121;
MAPLE
A094930 := proc(n, m) (3*m-1)*(3*m+3*n-2)*(n+1-m)/2 ; end: seq(seq(A094930(n, m), m=1..n), n=1..20) ; # R. J. Mathar, Oct 09 2009
CROSSREFS
KEYWORD
AUTHOR
Gary W. Adamson, Jun 17 2004
EXTENSIONS
Edited and extended by R. J. Mathar, Oct 09 2009
STATUS
approved