![]()  | 
Journal of Integer Sequences, Vol. 6 (2003), Article 03.3.3 | 
Abstract:
The integer sequences with first term 
 comprise a
group 
 under convolution, namely, the Appell group, and the
lower triangular infinite integer matrices with all diagonal entries 
comprise a group 
 under matrix multiplication.  If 
 and 
 then 
  The groups 
 and 
 and various subgroups are discussed.  These
include the group 
 of matrices whose columns are identical
except for initial zeros, and also the group 
 of matrices
in which the odd-numbered columns are identical except for initial zeros and
the same is true for even-numbered columns.  Conditions are determined for
the product of two matrices in 
 to be in 
  Conditions are also determined for two matrices in 
 to commute.
(Concerned with sequences A000045 A000108 A000142 A000201 A000204 A000741 A000984 A002530 A047749 A077049 A077050 A077605 A077606 .)
Received November 13, 2002; revised version received January 28, 2002; September 2, 2003. Published in Journal of Integer Sequences September 8, 2003.