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%I #23 Dec 18 2017 02:34:51
%S 1,1,3,1,1,4,1,1,1,7,1,1,1,1,11,1,3,2,1,1,18,1,1,1,1,1,1,29,1,1,1,1,1,
%T 1,1,47,1,1,4,1,1,2,1,1,76,1,3,1,1,1,3,1,1,1,123,1,1,1,1,1,1,1,1,1,1,
%U 199,1,1,2,7,1,2,1,1,2,1,1,322,1,1,1,1,1,1,1,1,1,1,1,1,521
%N Triangle read by rows: T(n,k) = gcd(Lucas(n), Lucas(k)), 1 <= k <= n.
%H Harvey P. Dale, <a href="/A111956/b111956.txt">Rows n = 1..141 of triangle, flattened</a>
%H Paulo Ribenboim, <a href="http://www.fq.math.ca/Papers1/43-1/paper43-1-1.pdf">FFF (Favorite Fibonacci Flowers)</a>, Fib. Quart. 43 (No. 1, 2005), 3-14.
%F T(n, k) = Lucas(g), where g = gcd(n, k), if n/g and k/g are odd; = 2 if n/g or k/g are even and 3|g; = 1 otherwise.
%t Flatten[Table[GCD[LucasL[n], LucasL[k]], {n,20}, {k,n}]] (* _Harvey P. Dale_, Nov 23 2012 *)
%o (PARI) for(n=1,10, for(k=1,n, print1(gcd(fibonacci(n+1) + fibonacci(n-1), fibonacci(k+1) + fibonacci(k-1)), ", "))) \\ _G. C. Greubel_, Dec 17 2017
%Y Cf. A000032, A111946, A111957.
%K nonn,tabl
%O 1,3
%A _N. J. A. Sloane_, Nov 28 2005
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