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 A212261 #19 Nov 30 2015 09:35:38 %S A212261 1,1,-1,1,-2,1,1,-3,12,-1,1,-4,33,-128,1,1,-5,64,-731,1872,-1,1,-6, %T A212261 105,-2160,25857,-37600,1,1,-7,156,-4765,121600,-1311379,990784,-1,1, %U A212261 -8,217,-8896,368145,-10138880,89060065,-32333824,1 %N A212261 Array A(i,j) read by antidiagonals: A(i,j) is the (2i-1)-th derivative of sin(sin(sin(...sin(x)))) nested j times evaluated at 0. %C A212261 The determinant of the n X n such matrix has a closed form given in the formula section (and the Mathematica code below). %C A212261 Rows appear to be given by polynomials (see formula section). %F A212261 A(i,j) = ((d/dx)^(2i-1) sin^j(x))_{x=0}. %F A212261 Let A_n denote the n X n such matrix. Then: %F A212261 det(A_n)=(i^(n + n^2) 2^(-(1/12) + n^2) 3^(n/2 - n^2/2) G^3 (-(1/pi))^n B(1/2 + n) B(1 + n) B(3/2 + n))/e^(1/4), where B is the Barnes G-function and G is the Glaisher-Kinkelin constant (and i is the imaginary unit). (This can be shown by evaluating recurrence relations for det(A_n)). See Mathematica code below. %F A212261 First row: 1. %F A212261 Second row: -x. %F A212261 Third row: x (5 x - 4). %F A212261 Fourth row: -(1/3) x (164 + 7 x (-48 + 25 x)). %F A212261 Fifth row: (8 - 7 x)^2 x (-24 + 25 x). %F A212261 Sixth row: -(1/3) x (213568 - 766656 x + 1004696 x^2 - 572880 x^3 + 121275 x^4). %F A212261 Seventh row: 1/3 x (-14371328 + 65012064 x - 111160192 x^2 + 91291200 x^3 - 36552516 x^4 + 5780775 x^5). %F A212261 Second column: A003712. %F A212261 Third column: A003715. %e A212261 Evaluate the fifth derivative of sin(sin(sin(x))) at 0, which is 33. So the (3,3) entry of the array is 33. The array begins as: %e A212261 | 1 1 1 1 1 1 | %e A212261 | -1 -2 -3 -4 -5 -6 | %e A212261 | 1 12 33 64 105 156 | %e A212261 | -1 -128 -731 -2160 -4765 -8896 | %e A212261 | 1 1872 25857 121600 368145 873936 | %e A212261 | -1 -37600 -1311379 -10138880 -42807605 -130426016 | %p A212261 A:= (i, j)-> (D@@(2*i-1))(sin@@j)(0): %p A212261 seq(seq(A(i, 1+d-i), i=1..d), d=1..9); # _Alois P. Heinz_, May 14 2012 %t A212261 A[a_, b_] := %t A212261 A[a, b] = %t A212261 Array[D[Nest[Sin, x, #2], {x, 2*#1 - 1}] /. x -> 0 &, {a, b}]; %t A212261 Print[A[7, 7] // MatrixForm]; %t A212261 Table2 = {}; %t A212261 k = 1; %t A212261 While[k < 8, Table1 = {}; %t A212261 i = 1; %t A212261 j = k; %t A212261 While[0 < j, %t A212261 AppendTo[Table1, First[Take[First[Take[A[7, 7], {i, i}]], {j, j}]]]; %t A212261 j = j - 1; %t A212261 i = i + 1]; %t A212261 AppendTo[Table2, Table1]; %t A212261 k++]; %t A212261 Print[Flatten[Table2]] %t A212261 Print[Table[Det[A[n, n]], {n, 1, 7}]]; %t A212261 Print[Table[( %t A212261 I^(n + n^2) 2^(-(1/12) + n^2) 3^(n/2 - n^2/2) %t A212261 Glaisher^3 (-(1/\[Pi]))^ %t A212261 n BarnesG[1/2 + n] BarnesG[1 + n] BarnesG[3/2 + n])/E^(1/4), {n, 1, 7}]] %Y A212261 Cf. A003712, A003715. %K A212261 sign,tabl,hard,nice %O A212261 1,5 %A A212261 _John M. Campbell_, May 12 2012