I’ve currently got the API set up to grab data from our Sage 200 platform and I’ve been asked to grab all invoices and what items they contained for a certain period.

Planar code is for storing planar graphs. See https://houseofgraphs.org/help#format_pc.

Consider the following equation:

My problem in sagemath is as follows, for simplification , given five polynomials $f_1(x,y,z)=-z-y+x+xy+2xy^2$, $f_2(x,y,z)=-z-y+x+xy$, $f_3(x,y,z)=-2z-y+5x$, $f_4(x,y,z)=z+y$, $f_5(x,y,z)=z$ . How to construct by sage the matrix whose the i-th row is coeffcients of the polynomial $f_i(x,y,z)$ .

Let $(5,r_1,r_2,r_3,0)$ be an integer sequence. I want to generate all possible sequences of this form subject to the following two constraints:
(ii) $r_i$’s are distinct;
(i) $|r_{i+1}-r_i|5$ for each $0le ile 3$ (where $r_0=4,r_4=0$).