Post #2658776

@christianp@mathstodon.xyz Wow! This extra ≈n^0.5 term actually precisely matches the index of n in a(n), when it is in the sequence (which happens very often, as mentioned) ! 😮 So for these cases we get a(n) = n(n+3)/2 - a.index(n) See the updated gist https://gist.github.com/hellman/a4a56f013085edf379ac6377db0fa9bb