%I A072229
%S A072229 0,0,0,0,1,2,3,4,4,4,4,5,6,7,8,8,8,8,9,10,11,12,12,12,12,13,14,15,16,16,
%T A072229 16,16,17,18,19,20,20,20,20,21,22,23,24,24,24,24,25,26,27,28,28,28,28,
%U A072229 29,30,31,32,32,32,32,33,34,35,36,36,36,36,37,38,39,40,40,40,40,41,42
%N A072229 Witt index of the standard bilinear form <1,1,1,...,1> over the 2-adic 
               rationals.
%C A072229 There is another interesting bilinear form over Q_2 : it is <1, ..., 
               1, 2>. It has Witt index 0, 0, 0, 1, 1, 2, 3, 3, 4, 4, 4, 5, 5, 6, 
               7, 7...
%F A072229 a(n) = 4 floor(n/7) + [0,0,0,0,1,2,3][n%7 + 1]. (Formula corrected by 
               Franklin T. Adams-Watters, Apr 13 2009)
%F A072229 a(n)=a(n-1)+a(n-7)-a(n-8). G.f.: x^4*(1+x)*(1+x^2)/((x^6+x^5+x^4+x^3+x^2+x+1)*(x-1)^2). 
               [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 16 2009]
%p A072229 for n from 0 to 120 do printf("%d,", 4*floor(n/7)+op( (n mod 7)+1, [0,
               0,0,0,1,2,3]) ) ; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Apr 16 2009]
%Y A072229 Sequence in context: A087848 A087844 A140427 this_sequence A120509 A029106 
               A064004
%Y A072229 Adjacent sequences: A072226 A072227 A072228 this_sequence A072230 A072231 
               A072232
%K A072229 nonn,nice,easy
%O A072229 0,6
%A A072229 G. Collinet (collinet(AT)math.polytechnique.fr), Jul 05 2002
%E A072229 More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 16 2009