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 A204204 #9 Dec 25 2013 02:29:56 %S A204204 3,3,7,3,10,15,3,13,25,31,3,16,38,56,63,3,19,54,94,119,127,3,22,73, %T A204204 148,213,246,255,3,25,95,221,361,459,501,511,3,28,120,316,582,820,960, %U A204204 1012,1023,3,31,148,436,898,1402,1780,1972,2035,2047,3,34,179 %N A204204 Triangle based on (0,3/4,1) averaging array. %C A204204 See A204201 for a discussion and guide to other averaging arrays. %F A204204 From _Philippe Deléham_, Dec 24 2013: (Start) %F A204204 T(n,n) = A000225(n+1). %F A204204 Sum_{k=1..n} T(n,k) = A128135(n+1). %F A204204 T(n,k)=T(n-1,k)+3*T(n-1,k-1)-2*T(n-2,k-1)-2*T(n-2,k-2), T(1,1)=3, T(2,1)=3, T(2,2)=7, T(n,k)=0 if k<1 or if k>n. (End) %e A204204 First six rows: %e A204204 3 %e A204204 3...7 %e A204204 3...10...15 %e A204204 3...13...25...31 %e A204204 3...16...38...56...63 %e A204204 3...19...54...94...119..127 %t A204204 a = 0; r = 3/4; b = 1; %t A204204 t[1, 1] = r; %t A204204 t[n_, 1] := (a + t[n - 1, 1])/2; %t A204204 t[n_, n_] := (b + t[n - 1, n - 1])/2; %t A204204 t[n_, k_] := (t[n - 1, k - 1] + t[n - 1, k])/2; %t A204204 u[n_] := Table[t[n, k], {k, 1, n}] %t A204204 Table[u[n], {n, 1, 5}] (* averaging array *) %t A204204 u = Table[3 (1/2) (1/r) 2^n*u[n], {n, 1, 12}]; %t A204204 TableForm[u] (* A204204 triangle *) %t A204204 Flatten[u] (* A204204 sequence *) %Y A204204 Cf. A204201. %K A204204 nonn,tabl %O A204204 1,1 %A A204204 _Clark Kimberling_, Jan 12 2012