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 A059424 #3 Mar 30 2012 16:49:02 %S A059424 0,0,1,3,9,35,195,1218,9184,75492,724995,7428905,86414559,1059030297, %T A059424 14455096201,206132138310,3228219898080,52501425954872, %U A059424 927663133292361,16944154401198843,333387373140423145,6756756713150677275,146490980301083247291 %N A059424 Number of negative terms in a symmetric determinant of order n. %D A059424 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 260, #12, p_n. %Y A059424 (A002135-A059422)/2. Cf. A059423. %K A059424 nonn %O A059424 0,4 %A A059424 _N. J. A. Sloane_, Jan 30 2001