G.f.：P（x，y）=1+（x+y）+（2*x^2+2*x*y+2*y^2）+（3*x^3+4*x^2*y+4*x*y^2+3*y^3）+（5*x^4+7*x^3*y+10*x^2*y^2+7*x*y^3+5*y^4）+（7*x^5+12*x^4*y+18*x^3*y^2+18*x^2*y^3+12*x*y^ 4+7*y^5）+（11*x^6+19*x^5*y+34*x^4*y^2+38*x^3*y^3+34*x^2*y^4+19*x*y^5+11*y^6）+（15*x^7+30*x^6*y+56*x^5*y^2+74*x^4*y^3+74*x ^3*y^4+56*y^5+30*x*y^6+15*y|7）+（22*x^8+45*x^7*y+94*x^6*y^2+133*x^5*y^3+158*x^4*y^4+133*x ^3*y^5+94*x ^2*y^6+45*y ^7+22*y^8）+。。。
这样的话
P（x，y）=产品{n>=1}1/（1-（x^n+y^n）），
哪里
P（x，y）=和{n>=0}和{k>=0{T（n，k）*x^n*y^k。
方形桌子。
P（x，y）中x^n*y^k的系数T（n，k）的平方表开始
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, 101, ...;
1, 2, 4, 7, 12, 19, 30, 45, 67, 97, 139, 195, 272, ...;
2, 4, 10, 18, 34, 56, 94, 146, 228, 340, 506, 730, ...;
3, 7, 18, 38, 74, 133, 233, 385, 623, 977, 1501, 2255, ...;
5, 12, 34, 74, 158, 297, 550, 951, 1614, 2627, 4202, 6531, ...;
7, 19, 56, 133, 297, 602, 1166, 2133, 3775, 6437, 10692, ...;
11, 30, 94, 233, 550, 1166, 2382, 4551, 8424, 14953, 25835, ...;
15, 45, 146, 385, 951, 2133, 4551, 9142, 17639, 32680, ...;
22, 67, 228, 623, 1614, 3775, 8424, 17639, 35492, 68356, ...;
30, 97, 340, 977, 2627, 6437, 14953, 32680, 68356, 136936, ...;
42, 139, 506, 1501, 4202, 10692, 25835, 58659, 127443, 264747, ...;
56, 195, 730, 2255, 6531, 17290, 43313, 102149, 229998, 495195, ...;
...
三角形。
或者，这个序列可以写成三角形，从
1;
1, 1;
2, 2, 2;
3, 4, 4, 3;
5, 7, 10, 7, 5;
7, 12, 18, 18, 12, 7;
11, 19, 34, 38, 34, 19, 11;
15, 30, 56, 74, 74, 56, 30, 15;
22, 45, 94, 133, 158, 133, 94, 45, 22;
30, 67, 146, 233, 297, 297, 233, 146, 67, 30;
42, 97, 228, 385, 550, 602, 550, 385, 228, 97, 42;
56, 139, 340, 623, 951, 1166, 1166, 951, 623, 340, 139, 56;
77, 195, 506, 977, 1614, 2133, 2382, 2133, 1614, 977, 506, 195, 77;
...
