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 A001439 #16 Jan 14 2023 03:06:17 %S A001439 0,0,0,0,1,0,1,1,1,3,7,1,120,398 %N A001439 Number of proper linear spaces of order n. %D A001439 CRC Handbook of Combinatorial Designs, 1996, p. 216. %Y A001439 Probably an erroneous version of A031436. %K A001439 nonn,hard %O A001439 3,10 %A A001439 _N. J. A. Sloane_