cp's OEIS Frontend

A374667 Triangle T(n,k) (1 <= k <= n) read by rows: T(n,k) = c_n * F(k)/F(k+2) where c_n = LCM of F(3), F(4), ... F(n+2) (and F() are the Fibonacci numbers).

%I A374667 #14 Jul 19 2024 19:23:27
%S A374667 1,3,2,15,10,12,60,40,48,45,780,520,624,585,600,5460,3640,4368,4095,
%T A374667 4200,4160,92820,61880,74256,69615,71400,70720,70980,1021020,680680,
%U A374667 816816,765765,785400,777920,780780,779688,90870780,60580520,72696624,68153085,69900600,69234880,69489420,69392232,69429360
%N A374667 Triangle T(n,k) (1 <= k <= n) read by rows: T(n,k) = c_n * F(k)/F(k+2) where c_n = LCM of F(3), F(4), ... F(n+2) (and F() are the Fibonacci numbers).
%F A374667 T(n,k) = A035105(n+2) * A000045(k) / A000045(k+2).
%e A374667 Triangle begins:
%e A374667       1;
%e A374667       3,     2;
%e A374667      15,    10,    12;
%e A374667      60,    40,    48,    45;
%e A374667     780,   520,   624,   585,   600;
%e A374667    5460,  3640,  4368,  4095,  4200,  4160;
%e A374667   92820, 61880, 74256, 69615, 71400, 70720, 70980;
%e A374667   ...
%e A374667 Fifth row is 780, 520, 624, 585, 600. These are 1/2, 1/3, 2/5, 3/8, 5/13 of c_5 = 1560.
%o A374667 (PARI) row(n)={my(m=lcm(vector(n,k,fibonacci(k+2)))); vector(n, k, fibonacci(k)*m/fibonacci(k+2))}
%Y A374667 Cf. A000045, A035105.
%K A374667 nonn,tabl
%O A374667 1,2
%A A374667 _J. Lowell_, Jul 15 2024