// output of ./demo/comb/bell-number-demo.cc:
// Description:
//% Aitken's array and Bell numbers.
//% Cf. OEIS sequence A011971: Aitken's array,
//% also called Bell triangle or Peirce triangle.

arg 1: 11 == N  [Show N rows]  default=11
 0:        1
 1:        1      2
 2:        2      3      5
 3:        5      7     10     15
 4:       15     20     27     37     52
 5:       52     67     87    114    151    203
 6:      203    255    322    409    523    674    877
 7:      877   1080   1335   1657   2066   2589   3263   4140
 8:     4140   5017   6097   7432   9089  11155  13744  17007  21147
 9:    21147  25287  30304  36401  43833  52922  64077  77821  94828 115975
10:   115975 137122 162409 192713 229114 272947 325869 389946 467767 562595 678570
