OFFSET
1,2
COMMENTS
For n>1, the order of the twisted Chevalley group (3)D_4(q).
REFERENCES
R. W. Carter, Simple Groups of Lie Type, Wiley 1972, Chap. 14, p. 262.
J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985 [for best online version see https://oeis.org/wiki/Welcome#Links_to_Other_Sites], p. xvi.
PROG
(Python)
from sympy import primepi, integer_nthroot
def A359129(n):
def f(x): return int(n-2+x-sum(primepi(integer_nthroot(x, k)[0]) for k in range(1, x.bit_length())))
kmin, kmax = 1, 2
while f(kmax) >= kmax:
kmax <<= 1
while True:
kmid = kmax+kmin>>1
if f(kmid) < kmid:
kmax = kmid
else:
kmin = kmid
if kmax-kmin <= 1:
break
return ((m:=kmax**2)*(m*(m*(m*(m*(m*(m*(m-1)+1)-2)+2)-2)+1)-1)+1)*m**6 # Chai Wah Wu, Aug 20 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 28 2022
STATUS
approved