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 A298883 #29 Jul 28 2019 16:43:32 %S A298883 1,2,6,180,50400,958003200,131514679296000,1352181326649753600000, %T A298883 112703642894318944282214400000, %U A298883 903025586371469323704949549301760000000,2012769637740033870687308804001121075357286400000000 %N A298883 Determinant of n X n matrix whose elements are m(i,j) = prime(i)^j. %C A298883 Traces of these matrices are A087480. %H A298883 Robert Israel, <a href="/A298883/b298883.txt">Table of n, a(n) for n = 0..35</a> %H A298883 Wikipedia, <a href="https://en.wikipedia.org/wiki/Vandermonde_matrix">Vandermonde matrix</a> %F A298883 a(n) = Product_{1<=i<=n} prime(i) * Product_{1<=i<j<=n} (prime(j)-prime(i)). - _Robert Israel_, Jan 29 2018 %e A298883 For n=1: %e A298883 |2| = 2, then a(1) = 2. %e A298883 For n=2: %e A298883 |2 4| = 6, then a(2) = 6. %e A298883 |3 9| %e A298883 For n=3: %e A298883 |2 4 8| = 180, then a(3) = 180. %e A298883 |3 9 27| %e A298883 |5 25 125| %p A298883 with(LinearAlgebra): %p A298883 a:= n-> Determinant(Matrix(n, (i,j)-> ithprime(i)^j)): %p A298883 seq(a(n), n=0..12); # _Alois P. Heinz_, Jan 28 2018 %p A298883 # Alternative: %p A298883 f:= proc(n) local P; %p A298883 P:= [seq(ithprime(i),i=1..n)]; %p A298883 convert(P,`*`)*mul(mul(P[j]-P[i],j=i+1..n),i=1..n-1) %p A298883 end proc: %p A298883 map(f, [$0..20]); # _Robert Israel_, Jan 29 2018 %t A298883 a[n_]:=Table[Prime[i]^j,{i,1,n},{j,1,n}]; %t A298883 Table[Det[a[n]],{n,1,10}] %o A298883 (PARI) a(n) = matdet(matrix(n, n, i, j, prime(i)^j)); \\ _Michel Marcus_, Jan 28 2018 %Y A298883 Cf. A080358, A087480, A298903. %K A298883 nonn %O A298883 0,2 %A A298883 _Andres Cicuttin_, Jan 28 2018