A377801 Irregular triangle read by rows: row n lists divisors of n-th Bell number.

1, 1, 1, 2, 1, 5, 1, 3, 5, 15, 1, 2, 4, 13, 26, 52, 1, 7, 29, 203, 1, 877, 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 23, 30, 36, 45, 46, 60, 69, 90, 92, 115, 138, 180, 207, 230, 276, 345, 414, 460, 690, 828, 1035, 1380, 2070, 4140, 1, 3, 7, 19, 21, 53, 57, 133, 159, 371, 399, 1007, 1113, 3021, 7049, 21147

Offset: 0

Author

Vincenzo Librandi, Nov 07 2024

Keywords

• nonn
• tabf

Examples

			Triangle begins:
  1,
  1,
  1,   2,
  1,   5,
  1,   3,  5,  15,
  1,   2,  4,  13, 26, 52,
  1,   7, 29, 203,
  1, 877,
  ...
		

Links

• Amiram Eldar, Table of n, a(n) for n = 0..7035 (rows 0..103 flattened)

Crossrefs

Cf. A000110, A027750, A279623.

Row sums give A262349.

Row lengths give A278973.

Programs

Magma

/* As triangle */ [Divisors(Bell(n)): n in [0..30]];

Mathematica

Flatten[Table[Divisors[BellB[n]], {n, 0, 20}]]

Formula

T(n,k) = A027750(A000110(n),k).

T(n,2) = A279623(n) for n>=2.