%I A006043 M2107
%S A006043 2,18,108,540,2430,10206,40824,157464,590490,2165130,7794468,
%T A006043 27634932,96722262,334807830,1147912560,3902902704,13172296626,
%U A006043 44165935746,147219785820,488149816140,1610894393262,5292938720718
%N A006043 A traffic light problem: expansion of 2/(1-3x)^3.
%C A006043 Column 2 of square array A152818. [From Omar E. Pol (info(AT)polprimos.com), 
               Jan 05 2009]
%D A006043 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A006043 F. A. Haight, Overflow at a traffic light, Biometrika, 46 (1959), 420-424.
%F A006043 a(n)=n*(n-1)*3^(n-2), n>=2 . - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               Apr 25 2007
%F A006043 a(n) = 3^n*(n+2)!/n!. [From Omar E. Pol (info(AT)polprimos.com), Jan 
               05 2009]
%p A006043 seq(n*(n-1)*3^(n-2), n=2..23); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               Apr 25 2007
%Y A006043 Cf. A006044, A000142, A152818, A154120. [From Omar E. Pol (info(AT)polprimos.com), 
               Jan 05 2009]
%Y A006043 Sequence in context: A005969 A094251 A101570 this_sequence A112328 A038721 
               A064837
%Y A006043 Adjacent sequences: A006040 A006041 A006042 this_sequence A006044 A006045 
               A006046
%K A006043 nonn,easy
%O A006043 0,1
%A A006043 N. J. A. Sloane (njas(AT)research.att.com), Simon Plouffe (simon.plouffe(AT)gmail.com)