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A104583
Triangle read by rows: T(i,j) is the (i,j)-entry (1 <= j <= i) of the product A*B of the matrices A = [1; 3,1; 5,3,1; 7,5,3,1; ...]; B = [1; 1,2; 1,2,1; 1,2,1,2; ...] (both infinite lower triangular matrices).
0
1, 4, 2, 9, 8, 1, 16, 18, 4, 2, 25, 32, 9, 8, 1, 36, 50, 16, 18, 4, 2, 49, 72, 25, 32, 9, 8, 1, 64, 98, 36, 50, 16, 18, 4, 2, 81, 128, 49, 72, 25, 32, 9, 8, 1, 100, 162, 64, 98, 36, 50, 16, 18, 4, 2, 121, 200, 81, 128, 49, 72, 25, 32, 9, 8, 1, 144, 242, 100, 162, 64, 98, 36, 50, 16, 18
OFFSET
0,2
FORMULA
T(i, j) = (i-j+1)^2 if j <= i and j is odd; 2(i-j+1)^2 if j <= i and j is even; 0 if j > i. - Emeric Deutsch, Mar 23 2005
EXAMPLE
The first few rows are:
1;
4, 2;
9, 8, 1;
16, 18, 4, 2;
25, 32, 9, 8, 1;
36, 50, 16, 18, 4, 2;
49, 72, 25, 32, 9, 8, 1;
...
MAPLE
T:=proc(i, j) if j<=i and j mod 2=1 then (i-j+1)^2 elif j<=i and j mod 2 =0 then 2*(i-j+1)^2 else 0 fi end: for i from 1 to 13 do seq(T(i, j), j=1..i) od; # yields sequence in triangular form # Emeric Deutsch, Mar 23 2005
CROSSREFS
Cf. A002411.
Row sums yield the pentagonal pyramidal numbers (A002411).
Sequence in context: A200639 A365255 A243968 * A278103 A249327 A182728
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Mar 16 2005
EXTENSIONS
More terms from Emeric Deutsch, Mar 23 2005
STATUS
approved