W. Lang, Sep 24 2008 a(n,m) tabl head (triangle) for A049404 (S1(-2)) n\m 1 2 3 4 5 6 7 8 9 10... 1 1 0 0 0 0 0 0 0 0 0 2 2 1 0 0 0 0 0 0 0 0 3 2 6 1 0 0 0 0 0 0 0 4 0 20 12 1 0 0 0 0 0 0 5 0 40 80 20 1 0 0 0 0 0 6 0 40 360 220 30 1 0 0 0 0 7 0 0 1120 1680 490 42 1 0 0 0 8 0 0 2240 9520 5600 952 56 1 0 0 9 0 0 2240 40320 48720 15120 1680 72 1 0 10 0 0 0 123200 332640 184800 35280 2760 90 1 . . . The row sums give A049425(n), n>=1: [1,3,9,33,141,651,3333,18369,108153,678771,...]. The first column is A008279(2,n-1), n>=1, [1,2,2,0,0,0,...]. The partition number array related to this triangle is A144358. ############################################ e.o.f. ###################################