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 A060923 #14 Mar 30 2024 13:24:17 %S A060923 1,4,1,11,17,1,29,80,39,1,76,303,315,70,1,199,1039,1687,905,110,1,521, %T A060923 3364,7470,6666,2120,159,1,1364,10493,29634,37580,20965,4311,217,1, %U A060923 3571,31885,109421,181074,148545 %N A060923 Bisection of Lucas triangle A060922: even-indexed members of column sequences of A060922 (not counting leading zeros). %F A060923 a(n, m) = A060922(2*n-m, m). %F A060923 a(n, m) = ((2*(n-m)+1)*A060924(n-1, m-1) + 2*(4*n-3*m)*a(n-1, m-1) + 4*(2*n-m-1)*A060924(n-2, m-1))/(5*m), m >= n >= 1; a(n, 0)= A002878(n); else 0. %F A060923 G.f. for column m >= 0: x^m*pLe(m+1, x)/(1-3*x+x^2)^(m+1), where pLe(n, x) := Sum_{m=0..n+floor(n/2)} A061186(n, m)*x^m are the row polynomials of the (signed) staircase A061186. %F A060923 T(n,k) = 3*T(n-1,k) + 2*T(n-1,k-1) - T(n-2,k) + 2*T(n-2,k-1) - T(n-2,k-2) + 4*T(n-3,k-2), T(0,0) = 1, T(1,0) = 4, T(1,1) = 1, T(2,0) = 11, T(2,1) = 17, T(2,2) = 1, T(n,k) = 0 if k < 0 or if k > n. - _Philippe Deléham_, Jan 21 2014 %e A060923 Triangle begins: %e A060923 {1}; %e A060923 {4,1}; %e A060923 {11,17,1}; %e A060923 {29,80,39,1}; %e A060923 ... %e A060923 pLe(2,x) = 1+11*x-11*x^2+4*x^3. %Y A060923 Row sums give A060926. %Y A060923 Column sequences (without leading zeros) are, for m=0..3: A002878, A060934-A060936. %Y A060923 Companion triangle A060924 (odd part). %Y A060923 Cf. A060922. %K A060923 nonn,easy,tabl %O A060923 0,2 %A A060923 _Wolfdieter Lang_, Apr 20 2001