%I A005190 M3456
%S A005190 1,1,4,12,44,155,580,2128,8092,30276,116304,440484,1703636,6506786,
%T A005190 25288120,97181760,379061020,1463609356,5724954544,22187304112,
%U A005190 86981744944,338118529539,1327977811076,5175023913008,20356299454276
%N A005190 Central quadrinomial coefficients: largest coefficient of (1+x+x^2+x^3)^n.
%C A005190 The maximal coefficient is that of x^[3n/2]. - M. F. Hasler (Maximilian.Hasler(AT)gmail.com), 
               Jul 23 2007
%D A005190 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A005190 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 78.
%D A005190 V. E. Hoggatt, Jr. and M. Bicknell, Diagonal sums of generalized Pascal 
               triangles, Fib. Quart., 7 (1969), 341-358, 393.
%H A005190 T. D. Noe, <a href="b005190.txt">Table of n, a(n) for n=0..200</a>
%F A005190 lim n -> infinity a(n+1)/a(n) = 4; for n>2 a(n+1) < 4*a(n) - Benoit Cloitre 
               (benoit7848c(AT)orange.fr), Sep 28 2002
%o A005190 (PARI) a(n)=vecmax(vector(3*n,i,polcoeff((1+x+x^2+x^3)^n,i,x)))
%o A005190 (PARI) A005190(n)=polcoeff((1+x+x^2+x^3)^n,(3*n)>>1) \\ M. F. Hasler
%Y A005190 Cf. A001405, A002426, A005191, A018901, A025012, A025013, A025014
%Y A005190 Sequence in context: A149359 A167402 A060897 this_sequence A149360 A149361 
               A149362
%Y A005190 Adjacent sequences: A005187 A005188 A005189 this_sequence A005191 A005192 
               A005193
%K A005190 nonn,easy
%O A005190 0,3
%A A005190 N. J. A. Sloane (njas(AT)research.att.com).