a(n,r) tabf head (staircase) for A062745 n\r 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 2 3 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 1 3 6 9 12 12 12 0 0 0 0 0 0 0 0 0 0 0 0 4 1 4 10 19 31 43 55 55 55 0 0 0 0 0 0 0 0 0 0 5 1 5 15 34 65 108 163 218 273 273 273 0 0 0 0 0 0 0 0 6 1 6 21 55 120 228 391 609 882 1155 1428 1428 1428 0 0 0 0 0 0 7 1 7 28 83 203 431 822 1431 2313 3468 4896 6324 7752 7752 7752 0 0 0 0 8 1 8 36 119 322 753 1575 3006 5319 8787 13683 20007 27759 35511 43263 43263 43263 0 0 9 1 9 45 164 486 1239 2814 5820 11139 19926 33609 53616 81375 116886 160149 203412 246675 246675 246675 . . . The sequence is, for rows n=0..10: [1, 1, 1, 1, 1, 2, 3, 3, 3, 1, 3, 6, 9, 12, 12, 12, 1, 4, 10, 19, 31, 43, 55, 55, 55, 1, 5, 15, 34, 65, 108, 163, 218, 273, 273, 273, 1, 6, 21, 55, 120, 228, 391, 609, 882, 1155, 1428, 1428, 1428, 1, 7, 28, 83, 203, 431, 822, 1431, 2313, 3468, 4896, 6324, 7752, 7752, 7752, 1, 8, 36, 119, 322, 753, 1575, 3006, 5319, 8787, 13683, 20007, 27759, 35511, 43263, 43263, 43263, 1, 9, 45, 164, 486, 1239, 2814, 5820, 11139, 19926, 33609, 53616, 81375, 116886, 160149, 203412, 246675, 246675, 246675, 1, 10, 55, 219, 705, 1944, 4758, 10578, 21717, 41643, 75252, 128868, 210243, 327129, 487278, 690690, 937365, 1184040, 1430715, 1430715, 1430715] ######################################################################################################################################