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 A370174 #14 Mar 25 2024 21:26:27
%S A370174 1,1,1,1,3,1,1,6,5,1,1,11,15,7,1,1,19,37,28,9,1,1,32,82,87,45,11,1,1,
%T A370174 53,170,234,169,66,13,1,1,87,337,573,535,291,91,15,1,1,142,647,1314,
%U A370174 1511,1061,461,120,17,1,1,231,1213,2871,3933,3398,1904,687,153,19,1
%N A370174 Triangle read by rows: Riordan array (1/(1 - x), x*(1 + x)/(1 - x - x^2)).
%F A370174 T(n,k) = T(n-1,k) + T(n-1,k-1) + T(n-2,k) + T(n-2,k-1), T(n,0) = 1, T(n,k) = 0 if k > n.
%F A370174 Sum_{k = 0..n} T(n,k)* x^k = A000012(n), A057960(n), A196472(n+1), A218988(n-1) for x = 0, 1, 2, 3 respectively.
%e A370174 Triangle T(n,k) begins:
%e A370174 k=0 1 2 3 4 5 6
%e A370174 n=0: 1;
%e A370174 n=1: 1, 1;
%e A370174 n=2: 1, 3, 1;
%e A370174 n=3: 1, 6, 5, 1;
%e A370174 n=4: 1, 11, 15, 7, 1;
%e A370174 n=5: 1, 19, 37, 28, 9, 1;
%e A370174 n=6: 1, 32, 82, 87, 45, 11, 1;
%e A370174 ...
%e A370174 87 = 28 + 37 + 7 + 15.
%Y A370174 Cf. A000012 (column k=0), A000384, A001911, A005408.
%Y A370174 Cf. A057960 (row sums), A196472, A218988.
%K A370174 nonn,tabl,easy
%O A370174 0,5
%A A370174 _Philippe Deléham_, Feb 29 2024