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 A143593 #5 Jun 02 2023 02:43:53 %S A143593 1,3,4,5,8,4,7,12,8,4,9,16,12,8,4,11,20,16,12,8,4,13,24,20,16,12,8,4, %T A143593 15,28,24,20,16,12,8,4,17,32,28,24,20,16,12,8,4,19,36,32,28,24,20,16, %U A143593 12,8,4 %N A143593 Triangle read by rows, square of A238303 (an infinite lower triangular matrix with 1's in the first column and the rest 2's). %C A143593 Row sums = A056220 starting with offset 1: (1, 7, 17, 31, 49, 71, 97,...). %F A143593 Triangle read by rows, square of an infinite lower triangular matrix with 1's in the first column and the rest 2's. Square of (A000012 * (S(k) * 0^(n-k)), 1<=k<=n %e A143593 The square of the infinite lower triangular matrix (1; 1,2; 1,2,2;...) = %e A143593 1; %e A143593 3, 4; %e A143593 5, 8, 4; %e A143593 7, 12, 8, 4; %e A143593 9, 16, 12, 8, 4; %e A143593 11, 20, 16, 12, 8, 4; %e A143593 13, 24, 20, 16, 12, 8, 4; %e A143593 ... %Y A143593 Cf. A056220, A238303. %K A143593 nonn,tabl %O A143593 1,2 %A A143593 _Gary W. Adamson_ & _Roger L. Bagula_, Aug 26 2008