Evaluate the sum
632−1+652−1+672−1+692−1+⋯
632−1+652−1+672−1+692−1+⋯=6(3−1)(3+1)+6(5−1)(5+1)+6(7−1)(7+1)+6(9−1)(9+1)+⋯=62⋅4+64⋅6+66⋅8+68⋅10+⋯=6(12⋅4+14⋅6+16⋅8+18⋅10+⋯)=6⋅∞∑k=112k(2k+2)=6⋅∞∑k=114k(k+1)=64⋅∞∑k=11k(k+1)=32⋅∞∑k=11k(k+1)|1k(k+1)=1k−1k+1=32⋅∞∑k=1(1k−1k+1)=32⋅[∞∑k=1(1k)−∞∑k=1(1k+1)]=32⋅[1+∞∑k=2(1k)−∞∑k=1(1k+1)]=32⋅[1+∞∑k=2(1k)−∞∑k=2(1k)]=32⋅(1+0)=32
A little toying with this and lookup at OEIS show that this sum is equal to34∞∑k=1 (k+12)−1=32
.Evaluate the sum
632−1+652−1+672−1+692−1+⋯
632−1+652−1+672−1+692−1+⋯=6(3−1)(3+1)+6(5−1)(5+1)+6(7−1)(7+1)+6(9−1)(9+1)+⋯=62⋅4+64⋅6+66⋅8+68⋅10+⋯=6(12⋅4+14⋅6+16⋅8+18⋅10+⋯)=6⋅∞∑k=112k(2k+2)=6⋅∞∑k=114k(k+1)=64⋅∞∑k=11k(k+1)=32⋅∞∑k=11k(k+1)|1k(k+1)=1k−1k+1=32⋅∞∑k=1(1k−1k+1)=32⋅[∞∑k=1(1k)−∞∑k=1(1k+1)]=32⋅[1+∞∑k=2(1k)−∞∑k=1(1k+1)]=32⋅[1+∞∑k=2(1k)−∞∑k=2(1k)]=32⋅(1+0)=32
Very nice, Heureka......I wondered if there was a way to determine this "by hand"
Hello Heureka,
In your solution, one of the (k) factors seems to have randomly evaporated:
32⋅∞∑k=11k⏟evaporated?(k+1)|1k+1=1k−1k+132⋅∞∑k=1(1k−1k+1)
I thought you would like to fix this fuckup.
GA