This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A111957 #21 Jan 05 2025 19:51:38 %S A111957 1,1,1,1,1,2,1,3,1,1,1,1,1,1,1,1,1,4,1,1,2,1,1,1,1,1,1,1,1,3,1,7,1,3, %T A111957 1,1,1,1,2,1,1,2,1,1,2,1,1,1,1,11,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,3, %U A111957 4,1,1,18,1,1,4,3,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,29,1,1,1,1,1,1 %N A111957 Triangle read by rows: T(n,k) = gcd(Fibonacci(n), Lucas(k)), 1 <= k <= n. %H A111957 G. C. Greubel, <a href="/A111957/b111957.txt">Table of n, a(n) for the first 50 rows, flattened</a> %H A111957 Paulo Ribenboim, <a href="https://web.archive.org/web/2024*/https://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 A111957 T(n, k) = Lucas(g), where g = gcd(n, k), if n/g is even; = 2 if n/g is odd and 3|g; = 1 otherwise. %e A111957 Triangle begins: %e A111957 1, %e A111957 1, 1, %e A111957 1, 1, 2, %e A111957 1, 3, 1, 1, %e A111957 1, 1, 1, 1, 1, %e A111957 1, 1, 4, 1, 1, 2, %e A111957 1, 1, 1, 1, 1, 1, 1, %e A111957 1, 3, 1, 7, 1, 3, 1, 1, %e A111957 1, 1, 2, 1, 1, 2, 1, 1, 2, %e A111957 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, %e A111957 ============================= %t A111957 Flatten[Table[GCD[Fibonacci[n], LucasL[k]], {n, 20}, {k, n}]] (* _Alonso del Arte_, Dec 19 2015 *) %o A111957 (Magma) /* As triangle */ [[Gcd(Fibonacci(n), Lucas(k)): k in [1..n]]: n in [1.. 15]]; // _Vincenzo Librandi_, Dec 20 2015 %Y A111957 Cf. A000045, A000032, A111946, A111956. %K A111957 nonn,tabl %O A111957 1,6 %A A111957 _N. J. A. Sloane_, Nov 28 2005