a(n,m) tabl head (triangle) for A115154 n\m 1 2 3 4 5 6 7 8 9 10 ... 0 1 0 0 0 0 0 0 0 0 0 1 1 4 0 0 0 0 0 0 0 0 2 1 13 25 0 0 0 0 0 0 0 3 1 40 115 190 0 0 0 0 0 0 4 1 121 466 1036 1606 0 0 0 0 0 5 1 364 1762 4870 9688 14506 0 0 0 0 6 1 1093 6379 20989 50053 93571 137089 0 0 0 7 1 3280 22417 85384 235543 516256 927523 1338790 0 0 8 1 9841 77092 333244 1039873 2588641 5371210 9387580 13403950 0 9 1 29524 260800 1260532 4380151 12146074 28259704 56422444 96634294 136846144 . . . Row sums give A115187: [1, 5, 39, 346, 3230, 31191, 309175, 3129194, 32211432, 336239668, ...] #################################################################################################