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 A245717 #12 Nov 05 2022 20:07:08
%S A245717 1,1,2,1,1,3,1,4,1,4,1,1,1,1,5,1,2,3,2,1,6,1,1,1,1,1,1,7,1,4,1,8,1,4,
%T A245717 1,8,1,1,9,1,1,9,1,1,9,1,2,1,2,5,2,1,2,1,10,1,1,1,1,1,1,1,1,1,1,11,1,
%U A245717 4,3,4,1,12,1,4,3,4,1,12,1,1,1,1,1,1,1,1,1,1,1,1,13
%N A245717 Triangle read by rows: T(n,k) = gcd(n,k^2), 1 <= k <= n.
%H A245717 Reinhard Zumkeller, <a href="/A245717/b245717.txt">Rows n = 1..125 of triangle, flattened</a>
%e A245717 First rows and their sums (A078430):
%e A245717 . 1: 1 1
%e A245717 . 2: 1, 2 3
%e A245717 . 3: 1, 1, 3 5
%e A245717 . 4: 1, 4, 1, 4 10
%e A245717 . 5: 1, 1, 1, 1, 5 9
%e A245717 . 6: 1, 2, 3, 2, 1, 6 15
%e A245717 . 7: 1, 1, 1, 1, 1, 1, 7 13
%e A245717 . 8: 1, 4, 1, 8, 1, 4, 1, 8 28
%e A245717 . 9: 1, 1, 9, 1, 1, 9, 1, 1, 9 33
%e A245717 . 10: 1, 2, 1, 2, 5, 2, 1, 2, 1, 10 27
%e A245717 . 11: 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11 21
%e A245717 . 12: 1, 4, 3, 4, 1, 12, 1, 4, 3, 4, 1, 12 50
%t A245717 Table[GCD[n,k^2],{n,15},{k,n}]//Flatten (* _Harvey P. Dale_, Nov 05 2022 *)
%o A245717 (Haskell)
%o A245717 a245717 n k = a245717_tabl !! (n-1) !! (k-1)
%o A245717 a245717_row n = a245717_tabl !! (n-1)
%o A245717 a245717_tabl = zipWith (zipWith gcd) a002024_tabl a133819_tabl
%o A245717 (PARI) row(n) = vector(n, k, gcd(n, k^2)); \\ _Michel Marcus_, Jan 24 2022
%Y A245717 Cf. A050873, A002024, A133819, A078430 (row sums).
%K A245717 nonn,tabl
%O A245717 1,3
%A A245717 _Reinhard Zumkeller_, Jul 30 2014