N边形数的性质（孔雀定理）

GeoGebra 命令及参数

1. Sequence((1; (i * α)), i, 0, n - 2) → vrepart
2. Sequence(Sum[vrepart, i], i, 1, n - 1) → srepart
3. Sequence(((n - 2) * i) - n + 3, i, 1, k) → suite
4. Sum(suite) → a
5. Sequence(A + (i; 0), i, 0, k - 1) → lhoriz
6. Sequence(Polygon[A + (0, 0), A + (i; 0), n], i, 1, k - 1) → l1
7. Sequence(Sequence[Sequence[A + (i * Element[srepart, j - 1]) + (t * Element[vrepart, j]), t, 1, i], j, 2, n - 1], i, 0, k - 1) → l2
8. Rotate(l1, π / n, A) → l1'
9. Sequence(Rotate[Element[l2, i], π / n, A], i, 1, Length[l2]) → l2'
10. Rotate(lhoriz, π / n, A) → lhoriz'
11. Sequence(Sequence[Polygon[Element[Element[Element[l2, 2], i], 1], Element[Element[Element[l2, m], i], 1], Element[Element[Element[l2, m], i], m - 1]], m, 2, k], i, 1, n - 2) → l4
12. Sequence(Rotate[Element[l4, i], π / n, A], i, 1, Length[l4]) → l4'
13. Element(l4', A1) → B1
14. Element(l4', A2) → B2
15. Element(l4', A3) → B3
16. Element(l4', A4) → B4
17. Element(l4', A5) → B5
18. Element(l4', A6) → B6
19. Element(l4', A7) → B7
20. Element(l4', A8) → B8
21. Element(l4', A9) → B9
22. Element(l4', A10) → B10
23. Element(l4', A11) → B11
24. Element(l4', A12) → B12
25. Element(l4', A13) → B13
26. Element(l4', A14) → B14
27. Element(l4', A15) → B15
28. Sequence(F - (0, (1.2 * i)), i, 0, k) → l3
29. Sequence(Text[" +" + (Element[suite, i]), Element[l3, i + 1] + (0.2, -0.1)], i, 1, n - 1) → l5