a(1)=1, a(n+1) = a(n) + p, where p is the largest prime < a(n) if a(n) is even and the smallest prime > a(n) if a(n) is odd.

A277224

a(1)=1, a(n+1) = a(n) + p, where p is the largest prime < a(n) if a(n) is even and the smallest prime > a(n) if a(n) is odd.