a(n,m) tabl head (triangle) for A001498 (Bessel polynomials) n\m 0 1 2 3 4 5 6 7 8 9 ... 0 1 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 2 1 3 3 0 0 0 0 0 0 0 3 1 6 15 15 0 0 0 0 0 0 4 1 10 45 105 105 0 0 0 0 0 5 1 15 105 420 945 945 0 0 0 0 6 1 21 210 1260 4725 10395 10395 0 0 0 7 1 28 378 3150 17325 62370 135135 135135 0 0 8 1 36 630 6930 51975 270270 945945 2027025 2027025 0 9 1 45 990 13860 135135 945945 4729725 16216200 34459425 34459425 . . . The row sums give A001515: [1, 2, 7, 37, 266, 2431, 27007, 353522, 5329837, 90960751,...]. The alternating row sums give A000806: [1, 0, 1, -5, 36, -329, 3655, -47844, 721315, -12310199,...]. ########################################## e.o.f. #######################################################