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 A218016 #45 Sep 08 2022 08:46:04 %S A218016 1,5,1,25,10,2,125,75,30,6,625,500,300,120,24,3125,3125,2500,1500,600, %T A218016 120,15625,18750,18750,15000,9000,3600,720,78125,109375,131250,131250, %U A218016 105000,63000,25200,5040,390625,625000,875000,1050000,1050000,840000,504000,201600,40320 %N A218016 Triangle, read by rows, where T(n,k) = k!*C(n, k)*5^(n-k) for n>=0, k=0..n. %C A218016 Triangle formed by the derivatives of x^n evaluated at x=5. %C A218016 Sum(T(n,k), k=0..n) = A080954(n) (see the Formula section of A080954). . Also: %C A218016 first column: A000351; %C A218016 second column: A053464; %C A218016 third column: 2*A084902; %C A218016 fourth column: 6*A081143. %H A218016 Vincenzo Librandi, <a href="/A218016/b218016.txt">Rows n = 0..100, flattened</a> %F A218016 T(n,k) = 5^(n-k)*n!/(n-k)! for n>=0, k=0..n. %F A218016 E.g.f. (by columns): exp(5x)*x^k. %e A218016 Triangle begins: %e A218016 1; %e A218016 5, 1; %e A218016 25, 10, 2; %e A218016 125, 75, 30, 6; %e A218016 625, 500, 300, 120, 24; %e A218016 3125, 3125, 2500, 1500, 600, 120; %e A218016 15625, 18750, 18750, 15000, 9000, 3600, 720; %e A218016 78125, 109375, 131250, 131250, 105000, 63000, 25200, 5040; %e A218016 390625, 625000, 875000, 1050000, 1050000, 840000, 504000, 201600, 40320; etc. %t A218016 Flatten[Table[n!/(n-k)!*5^(n-k), {n, 0, 10}, {k, 0, n}]] %o A218016 (Magma) [Factorial(n)/Factorial(n-k)*5^(n-k): k in [0..n], n in [0..10]]; %Y A218016 Cf. A000351, A053464, A080954, A081143, A084902, A090802, A217629, A218017. %K A218016 nonn,tabl,easy %O A218016 0,2 %A A218016 _Vincenzo Librandi_, Nov 10 2012