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 A106476 #10 Nov 16 2024 02:58:36
%S A106476 1,1,1,2,1,1,2,2,1,1,4,2,2,1,1,2,4,2,2,1,1,6,2,4,2,2,1,1,4,6,2,4,2,2,
%T A106476 1,1,6,4,6,2,4,2,2,1,1,4,6,4,6,2,4,2,2,1,1,10,4,6,4,6,2,4,2,2,1,1,4,
%U A106476 10,4,6,4,6,2,4,2,2,1,1,12,4,10,4,6,4,6,2,4,2,2,1,1,6,12,4,10,4,6,4,6,2,4,2,2,1,1
%N A106476 Sequence array of Euler phi function.
%C A106476 Row sums are A002088(n+1). Diagonal sums are A106477. Riordan array (1/Sum_{j>=0} A106479(j)*x^j, x).
%F A106476 Triangle T(n, k) = if(k <= n, phi(n-k+1), 0).
%e A106476 Triangle begins:
%e A106476 1;
%e A106476 1,1;
%e A106476 2,1,1;
%e A106476 2,2,1,1;
%e A106476 4,2,2,1,1;
%e A106476 2,4,2,2,1,1;
%t A106476 T[n_, k_] := If[k <= n, EulerPhi[n - k + 1], 0]; Table[T[n, k], {n, 0, 13}, {k, 0, n}] // Flatten (* _Amiram Eldar_, Nov 16 2024 *)
%Y A106476 Cf. A000010, A002088, A106477, A106478, A106479, A106480.
%K A106476 easy,nonn,tabl
%O A106476 0,4
%A A106476 _Paul Barry_, May 03 2005