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 A119508 #11 Jul 28 2021 16:54:19
%S A119508 1,0,-16,80,-4640,-1696,-47290368,778240,-1252408320,827269120,
%T A119508 -1883587535170560,-167527809024,-660985839681085440,
%U A119508 -66300178824585216,-1744375183677849600,29157688117836220727296,5544673967679230591621398528,-134078707495836661579776
%N A119508 Determinant of n X n matrix of first n^2 terms of Euler totient function phi (A000010).
%H A119508 Harvey P. Dale, <a href="/A119508/b119508.txt">Table of n, a(n) for n = 1..250</a>
%e A119508 a(2) = 0 because of the singular matrix 0 =
%e A119508 |1 1|
%e A119508 |2 2|.
%t A119508 nmax = 20; Table[Det[Table[EulerPhi[k*(i-1) + j], {i, 1, k}, {j, 1, k}]], {k, 1, nmax}] (* _Vaclav Kotesovec_, Feb 24 2019 *)
%t A119508 Table[Det[Partition[EulerPhi[Range[n^2]],n]],{n,20}] (* _Harvey P. Dale_, Jul 28 2021 *)
%Y A119508 Cf. A000010, A119493.
%K A119508 easy,sign
%O A119508 1,3
%A A119508 _Jonathan Vos Post_, May 27 2006
%E A119508 More terms from _Vaclav Kotesovec_, Feb 24 2019