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 A176891 #7 Aug 08 2016 19:49:33 %S A176891 1,1,0,1,0,0,1,2,0,0,1,0,0,0,0,1,2,3,0,0,0,1,0,0,0,0,0,0,1,2,0,4,0,0, %T A176891 0,0,1,0,3,0,0,0,0,0,0,1,2,0,0,5,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,2, %U A176891 3,4,0,6,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,2,0,0,0,0,7,0,0,0,0,0,0,0 %N A176891 Triangle T(n,k) = k if k<n and k|n, = 0 otherwise, 1 <= k <= n; read by rows. %C A176891 A variant of A127093, which has T(n,n) = n. [The original definition said "Subsequence of A127093". Since all nonnegative integers are repeated infinitely often in both sequences, each one is a subsequence of the other, but there is no such relation on a row-by-row basis. - _M. F. Hasler_, Aug 08 2016] %C A176891 Let A=A176891*A176891, B=A*A, C=B*B, D=C*C and so on, then the leftmost column in the last matrix (D) converges to A165552. %F A176891 T(n,k) = if n=1 and k=1 then 1 elseif n=k then 0 elseif k divides n then k else 0. %e A176891 Triangle begins: %e A176891 1, %e A176891 1,0, %e A176891 1,0,0, %e A176891 1,2,0,0, %e A176891 1,0,0,0,0, %e A176891 1,2,3,0,0,0, %e A176891 1,0,0,0,0,0,0, %e A176891 1,2,0,4,0,0,0,0, %Y A176891 Cf. A127093, A165552. %K A176891 nonn,tabl %O A176891 1,8 %A A176891 _Gary W. Adamson_ and _Mats Granvik_, Apr 28 2010 %E A176891 Definition corrected by _M. F. Hasler_, Aug 08 2016