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 A143966 #5 Feb 08 2022 22:11:26 %S A143966 1,2,1,2,2,3,2,2,6,7,2,2,6,14,17,2,2,6,14,34,41,2,2,6,14,34,82,99,2,2, %T A143966 6,14,34,82,198,239,2,2,6,14,34,82,198,478,577 %N A143966 Eigentriangle with row sums = A001333 starting (1, 3, 7, 17, 41, 99, ...). %C A143966 Right border = A001333. %C A143966 Row sums = shifted A001333: (1, 3, 7, 17, 41, 99, ...) = INVERT transform of (1, 2, 2, 2, ...). Sum of n-th row terms = rightmost term of next row. %F A143966 n-th row of the triangle = n terms of twice A001333: (1, 1, 3, 7, 17, 41, 99, ...) followed by A001333(n). %e A143966 First few rows of the triangle: %e A143966 1; %e A143966 2, 1; %e A143966 2, 2, 3; %e A143966 2, 2, 6, 7; %e A143966 2, 2, 6, 14, 17; %e A143966 2, 2, 6, 14, 34, 41; %e A143966 2, 2, 6, 14, 34, 82, 99; %e A143966 2, 2, 6, 14, 34, 82, 198, 239; %e A143966 ... %Y A143966 Cf. A001333. %K A143966 nonn,tabl %O A143966 0,2 %A A143966 _Gary W. Adamson_, Sep 06 2008