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 A181670 #12 Jun 29 2024 16:12:32
%S A181670 1,0,2,0,1,4,0,2,3,1,0,1,1,2,5,0,2,2,4,10,6,0,1,4,1,9,12,13,0,2,3,2,7,
%T A181670 11,9,14,0,1,1,4,3,9,1,9,3,0,2,2,1,6,5,2,18,6,19,0,1,4,2,1,10,4,17,12,
%U A181670 9,1,0,2,3,4,2,7,8,15,1,18,2,13,0,1,1,1,4,1,16,11,2,7,4,26,37,0,2,2,2,8,2,15
%N A181670 Triangle read by rows: T(n,k) = 2^(n-1) mod prime(k), 1 <= k <= n.
%e A181670 Triangle begins:
%e A181670 1;
%e A181670 0, 2;
%e A181670 0, 1, 4;
%e A181670 0, 2, 3, 1;
%e A181670 0, 1, 1, 2, 5;
%e A181670 0, 2, 2, 4,10, 6;
%e A181670 0, 1, 4, 1, 9,12,13;
%e A181670 0, 2, 3, 2, 7,11, 9,14;
%e A181670 0, 1, 1, 4, 3, 9, 1, 9, 3;
%t A181670 Flatten[Table[Mod[2^(n-1),Prime[k]],{n,14},{k,n}]]
%Y A181670 Cf. A174620.
%K A181670 nonn,tabl
%O A181670 1,3
%A A181670 _Juri-Stepan Gerasimov_, Dec 02 2010
%E A181670 Corrected by _T. D. Noe_, Dec 02 2010