%I A005565 M5087
%S A005565 20,75,189,392,720,1215,1925,2904,4212,5915,8085,10800,14144,18207,
%T A005565 23085,28880,35700,43659,52877,63480,75600,89375,104949,122472,142100
%N A005565 Number of walks on square lattice.
%D A005565 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A005565 S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques 
               Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 
               1992.
%H A005565 S. Plouffe, <a href="http://www.lacim.uqam.ca/%7Eplouffe/articles/MasterThesis.pdf">
               Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures</
               a>, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 
               1992.
%H A005565 S. Plouffe, <a href="http://www.lacim.uqam.ca/%7Eplouffe/articles/FonctionsGeneratrices.pdf">
               1031 Generating Functions and Conjectures</a>, Universit\'{e} du 
               Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
%H A005565 R. K. Guy, Catwalks, Sandsteps and Pascal Pyramids, <a href="http://www.cs.uwaterloo.ca/
               journals/JIS/index.html">J. Integer Seqs., Vol. 3 (2000), #00.1.6</
               a>
%F A005565 1/4*(n^4+14n^3+69n^2+136n+80). G.f.: (20-25x+14x^2-3x^3)/(1-x)^5. - Ralf 
               Stephan, Apr 23 2004
%p A005565 seq(add (k^3-n^2, k =0..n), n=4..28 ); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               Aug 26 2007
%p A005565 A005565:=(-20+25*z-14*z**2+3*z**3)/(z-1)**5; [Conjectured by S. Plouffe 
               in his 1992 dissertation.]
%Y A005565 Sequence in context: A002292 A010008 A000529 this_sequence A066126 A083127 
               A002609
%Y A005565 Adjacent sequences: A005562 A005563 A005564 this_sequence A005566 A005567 
               A005568
%K A005565 nonn
%O A005565 0,1
%A A005565 N. J. A. Sloane (njas(AT)research.att.com).