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

0,4

Links

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

Formula

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

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

Example

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

Mathematica

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

Prog

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

Crossrefs

Cf. A000110, A027750, A279623.

Row sums give A262349.

Row lengths give A278973.

Sequence in context: A055205 A342001 A347957 * A369038 A161686 A289621

Adjacent sequences: A377798 A377799 A377800 * A377802 A377803 A377804

Keyword

nonn,tabf

Author

Vincenzo Librandi, Nov 07 2024

Status

approved