Search: id:A001231 Results 1-1 of 1 results found. %I A001231 %S A001231 1,1,1,1,0,1,1,4,0 %N A001231 Number of nonisomorphic projective planes of order n. %C A001231 The Bruck-Ryser theorem says that a(n)=0 if n == 1 or 2 (mod 4) and is not the sum of two squares. %D A001231 CRC Handbook of Combinatorial Designs, 1996, p. 695. %D A001231 Handbook of Combinatorics, North-Holland '95, p. 672. %D A001231 C. W. H. Lam, The Search for a Finite Projective Plane of Order 10, American Mathematical Monthly, 98, (no. 4) 1991, 305 - 318. %D A001231 C. W. H. Lam, G. Kolesova and S. Swiercz, A computer search for finite projective planes of order 9, Discrete Math., 92 (1991), 187-195. %D A001231 C. W. H. Lam, L. Thiel and S. Swiercz, The non-existence of finite projective planes of order 10, Canad. J. Math., 41 (1989), 1117-1123. %H A001231 C. W. H. Lam, Publications %H A001231 Ed Pegg, Jr., Finite affines planes of low orders %H A001231 N. J. A. Sloane, My favorite integer sequences, in Sequences and their Applications (Proceedings of SETA '98). %H A001231 Eric Weisstein's World of Mathematics, Projective Planes %Y A001231 Sequence in context: A058473 A115527 A050920 this_sequence A141150 A089418 A124856 %Y A001231 Adjacent sequences: A001228 A001229 A001230 this_sequence A001232 A001233 A001234 %K A001231 nonn,hard,nice %O A001231 2,8 %A A001231 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.002 seconds