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 A059423 #3 Mar 30 2012 16:49:02 %S A059423 1,1,1,2,8,38,193,1243,8971,77039,711719,7557974,85038784,1075040038, %T A059423 14252911927,208885729397,3187988600057,53129157538097, %U A059423 917244939572929,17127419083026706,329981266766790136,6823452191056396526,145118585159785011041 %N A059423 Number of positive terms in a symmetric determinant of order n. %D A059423 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 260, #12, p_n. %Y A059423 (A002135+A059422)/2. Cf. A059424. %K A059423 nonn %O A059423 0,4 %A A059423 _N. J. A. Sloane_, Jan 30 2001