Sum of Lucas numbers
From specialfunctionswiki
Theorem
The following formula holds: $$\displaystyle\sum_{k=1}^n L(k) = L(n+2)-3,$$ where $L(k)$ denotes the $k$th Lucas number.
The following formula holds: $$\displaystyle\sum_{k=1}^n L(k) = L(n+2)-3,$$ where $L(k)$ denotes the $k$th Lucas number.