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 A206819 #9 Feb 22 2013 14:40:25
%S A206819 1,10,1,90,20,1,800,280,30,1,7100,3400,570,40,1,63000,38300,8800,960,
%T A206819 50,1,559000,412000,120600,18000,1450,60,1,4960000,4296000,1530000,
%U A206819 291000,32000,2040,70,1
%N A206819 Riordan array (1/(1-10*x-10*x^2), x/(1-10*x-10*x^2)).
%C A206819 Row sums are A000042(n+1).
%C A206819 Subtriangle of triangle given by (0, 10, -1, 1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.
%F A206819 T(n,k) = 10*T(n-1,k) - 10*T(n-2,k) + T(n-1,k-1).
%F A206819 G.f.: 1/(1-10*x+10*x^2-y*x).
%F A206819 Sum_{k, 0<=k} T(n,k)*x^k = A178869(n+1), A057086(n), A000042(n+1) for x = -1, 0, 1 respectively.
%e A206819 Triangle begins :
%e A206819 1
%e A206819 10, 1
%e A206819 90, 20, 1
%e A206819 800, 280, 30, 1
%e A206819 7100, 3400, 570, 40, 1
%e A206819 63000, 38300, 8800, 960, 50, 1
%e A206819 559000, 412000, 120600, 18000, 1450, 60, 1
%e A206819 4960000, 4296000, 1530000, 291000, 32000, 2040, 70, 1
%e A206819 Triangle (0, 10, -1, 1, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, ...) begins :
%e A206819 1
%e A206819 0, 1
%e A206819 0, 10, 1
%e A206819 0, 90, 20, 1
%e A206819 0, 800, 280, 30, 1
%e A206819 0, 7100, 3400, 570, 40, 1 ...
%Y A206819 Cf. A101950, A178865,
%K A206819 easy,nonn,tabl
%O A206819 0,2
%A A206819 _Philippe Deléham_, Feb 12 2012