reviewed
approved
proposed
editing
D. Gault & and M. Clint, <a href="/A005206/a005206.pdf">"Curiouser and curiouser said Alice. Further reflections on an interesting recursive function</a>, Intern. J. Computer. Math., 26 (1988), 35-43. (Annotated scanned copy)
(Python)
from math import isqrt
def A001468(n): return (n+1+isqrt(m:=5*(n+1)**2)>>1)-(n+isqrt(m-10*n-5)>>1) # Chai Wah Wu, Aug 25 2022
return a[:length] # Nicholas Stefan Georgescu, Jun 02 2022