OFFSET
0,2
COMMENTS
MATHEMATICA
Accumulate @ Array[Floor @ Sqrt[4*# + 1] &, 100, 0] (* Amiram Eldar, Mar 19 2021 *)
PROG
(PARI) a(n) = sum(i=0, n, sqrtint(4*i+1)); \\ Michel Marcus, Mar 19 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Slav E. Angelov, Mar 19 2021
STATUS
approved