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

Author

T. D. Noe, Mar 14 2014

Keywords

• nonn
• tabf

Comments

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

Examples

			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;
  ...
		

Links

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

Crossrefs

Cf. A000032 (Lucas numbers), A027750.

Cf. A133021 (similar triangle for Fibonacci numbers).

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

Programs

Magma

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

Mathematica

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