A238899 Irregular triangle read by rows: row n lists divisors of n-th Lucas number A000032(n).

1, 2, 1, 1, 3, 1, 2, 4, 1, 7, 1, 11, 1, 2, 3, 6, 9, 18, 1, 29, 1, 47, 1, 2, 4, 19, 38, 76, 1, 3, 41, 123, 1, 199, 1, 2, 7, 14, 23, 46, 161, 322, 1, 521, 1, 3, 281, 843, 1, 2, 4, 11, 22, 31, 44, 62, 124, 341, 682, 1364, 1, 2207, 1, 3571, 1, 2, 3, 6, 9, 18, 27, 54

Offset

0,2

Comments

Note that, in general, the Lucas numbers have fewer divisors than Fibonacci numbers. Why?

Links

T. D. Noe, Rows 0 to 100 of irregular triangle, flattened

Example

Triangle begins:
  1,   2;
  1;
  1,   3;
  1,   2,  4;
  1,   7;
  1,  11;
  1,   2,  3,   6,  9, 18;
  1,  29;
  1,  47;
  1,   2,  4,  19, 38, 76;
  1,   3, 41, 123;
  1, 199;
  1,   2,  7,  14, 23, 46, 161, 322;
  ...

Mathematica

Flatten[Table[Divisors[LucasL[n]], {n, 0, 20}]] (* Typo corrected by Harvey P. Dale, Jun 29 2021 *)

Prog

(Magma) [Divisors(Lucas(n)): n in [0..30]]; // Vincenzo Librandi, Nov 15 2024

Crossrefs

Cf. A000032 (Lucas numbers), A027750.

Cf. A133021 (similar triangle for Fibonacci numbers).

Column 2 gives A280104 (for n>=2).

Sequence in context: A187846 A181087 A029288 * A187207 A050117 A241187

Adjacent sequences: A238896 A238897 A238898 * A238900 A238901 A238902

Keyword

nonn,tabf

Author

T. D. Noe, Mar 14 2014

Status

approved