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 A123743 #3 Mar 31 2012 13:20:13 %S A123743 1,2,12,1440,7257600,4981616640000,1190690865178214400000, %T A123743 272795714695463271824306995200000, %U A123743 157357907118293002525216789633250308915200000000 %N A123743 Certain Vandermonde determinants with Fibonacci numbers. %C A123743 The determinant of a Vandermonde matrix VM_n with elements VM_n[i,j]=(x_j)^i, i,j,=1..n, is VdmII([x_1,...,x_n]) := Det(VM_n)= product(x_k,k=1,...,n)*product(x_j - x_i, 1<=i<j<=n) if n>=2. For n=1, Det(VM_1)=1. %F A123743 a(n)= Fibfac(n)* |A123742(n)|, with the Fibonacci factorials Fibfac(n):=A003266(n+1). %F A123743 a(n)=VdmII([F(2),F(3),...,F(n+1)]) := Det(VM_n[i,j]) with the Vandermonde matrix elements VM_n[i,j]:=F(j+1)^i, i,j,=1..n and F(k):=A000045(k) (Fibonacci). %e A123743 n=4: VM_4 = matrix([1,2,3,5],[1,4,9,25],[1,8,27,125],[1,16,81,625]). %e A123743 a(4)=Det(VM_4) = 1440 = 30*48 = A003266(5)*|A123742(4)|. %Y A123743 Cf. A123742 (another version). %K A123743 nonn,easy %O A123743 1,2 %A A123743 _Wolfdieter Lang_ Oct 13 2006