Thaum cov chaw ua hlau tsim cov khoom siv ntau lawmcov kav hlau, lawv muab lawv ntim rau hauv cov duab hexagonal kom yooj yim thauj thiab suav. Txhua pob muaj rau lub raj rau ib sab. Muaj pes tsawg lub raj hauv txhua pob?
Lus Teb: 3n(n-1)+1, qhov twg n yog tus naj npawb ntawm cov kav dej ntawm ib sab ntawm lub hexagon sab nraud tshaj plaws. 1) * 6 = 6 cov kav dej, ntxiv rau 1 cov kav dej hauv nruab nrab.
Kev rho tawm ntawm cov mis:
Txhua sab tuav n cov kav dej. Txheej sab nraud tshaj plaws muaj (n-1) * 6 cov kav dej, txheej thib ob (n-2) * 6 cov kav dej, ..., txheej (n-1) thib (n-(n-1)) * 6 = 6 cov kav dej, thiab thaum kawg muaj 1 cov kav dej nyob hauv nruab nrab. Tag nrho yog [(n-1) + (n-2) + ... + 1]*6 + 1. Cov lus hauv cov ntawv cim qhia sawv cev rau qhov sib ntxiv ntawm cov lej lej (qhov sib ntxiv ntawm thawj thiab kawg cov lus faib los ntawm 2, tom qab ntawd muab n-1 ntxiv kom tau n*(n-1)/2).
Qhov no thaum kawg ua rau 3n * (n - 1) + 1.
Tus qauv: 3n(n-1)+1 Hloov n=8 rau hauv tus qauv: 3×8(8-1)+1 = 24×7+1 = 168+1 = 169 tus pas
Lub sijhawm tshaj tawm: Lub Kaum Hli-20-2025
