通用公式:A(x,q)=1+x*(1)+x^2*(1+q)+x*3*(1+2*q+q^2+q^3)
+x^4*(1+3*q+3*q^2+3*qq^3+2*q^4+q^5+q^6)
+x^5*(1+4*q+6*q^2+7*q^3+7*q ^4+5*q^5+5*q ^6+3*q ^7+2*q ^8+q ^9+q ^10)
+x^6*(1+5*q+10*q^2+14*q^3+17*q^4+16*q^5+16*q ^6+14*q ^7+11*q ^8+9*q^9+7*q^10+5*q^11+3*q^12+2*q^13+q^14+q^15)+。。。
其中g.f.:
A(x,q)=和{k=0..n*(n-1)/2,n>=0}T(n,k)*x^n*q^k
满足:
A(x,q)=1+x*A(q*x,q。
A(x,q)中系数T(n,k)的三角形开始于:
1;
1;
1, 1;
1, 2, 1, 1;
1, 3, 3, 3, 2, 1, 1;
1, 4, 6, 7, 7, 5, 5, 3, 2, 1, 1;
1, 5, 10, 14, 17, 16, 16, 14, 11, 9, 7, 5, 3, 2, 1, 1;
1, 6, 15, 25, 35, 40, 43, 44, 40, 37, 32, 28, 22, 18, 13, 11, 7, 5, 3, 2, 1, 1;
1, 7, 21, 41, 65, 86, 102, 115, 118, 118, 113, 106, 96, 85, 73, 63, 53, 42, 34, 26, 20, 15, 11, 7, 5, 3, 2, 1, 1;
1, 8, 28, 63, 112, 167, 219, 268, 303, 326, 338, 338, 331, 314, 293, 268, 245, 215, 190, 162, 139, 116, 97, 77, 63, 48, 38, 28, 22, 15, 11, 7, 5, 3, 2, 1, 1; ...