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

%I A238899 #20 Nov 15 2024 12:56:01
%S A238899 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,
%T A238899 41,123,1,199,1,2,7,14,23,46,161,322,1,521,1,3,281,843,1,2,4,11,22,31,
%U A238899 44,62,124,341,682,1364,1,2207,1,3571,1,2,3,6,9,18,27,54
%N A238899 Irregular triangle read by rows: row n lists divisors of n-th Lucas number A000032(n).
%C A238899 Note that, in general, the Lucas numbers have fewer divisors than Fibonacci numbers. Why?
%H A238899 T. D. Noe, <a href="/A238899/b238899.txt">Rows 0 to 100 of irregular triangle, flattened</a>
%e A238899 Triangle begins:
%e A238899   1,   2;
%e A238899   1;
%e A238899   1,   3;
%e A238899   1,   2,  4;
%e A238899   1,   7;
%e A238899   1,  11;
%e A238899   1,   2,  3,   6,  9, 18;
%e A238899   1,  29;
%e A238899   1,  47;
%e A238899   1,   2,  4,  19, 38, 76;
%e A238899   1,   3, 41, 123;
%e A238899   1, 199;
%e A238899   1,   2,  7,  14, 23, 46, 161, 322;
%e A238899   ...
%t A238899 Flatten[Table[Divisors[LucasL[n]], {n, 0, 20}]] (* Typo corrected by _Harvey P. Dale_, Jun 29 2021 *)
%o A238899 (Magma) [Divisors(Lucas(n)): n in [0..30]]; // _Vincenzo Librandi_, Nov 15 2024
%Y A238899 Cf. A000032 (Lucas numbers), A027750.
%Y A238899 Cf. A133021 (similar triangle for Fibonacci numbers).
%Y A238899 Column 2 gives A280104 (for n>=2).
%K A238899 nonn,tabf
%O A238899 0,2
%A A238899 _T. D. Noe_, Mar 14 2014