OFFSET
1,2
COMMENTS
How fast is this growing?
LINKS
N. J. A. Sloane, Table of n, a(n) for n = 1..16383
MATHEMATICA
Accumulate[(Sqrt[1+8#]-1)/2&/@Flatten[With[{r=Accumulate[ Range[ 300]]}, Table[ Select[ r, Divisible[#, n]&, 1], {n, 80}]]]] (* Harvey P. Dale, Sep 19 2021 *)
PROG
(Python 3.8+)
from itertools import combinations, count, islice
from math import prod
from sympy import factorint
from sympy.ntheory.modular import crt
def A345984_gen(): # generator of terms
c = 1
for n in count(4, 2):
yield c
plist = tuple(p**q for p, q in factorint(n).items())
c += n-1 if len(plist) == 1 else int(min(min(crt((m, n//m), (0, -1))[0], crt((n//m, m), (0, -1))[0]) for m in (prod(d) for l in range(1, len(plist)//2+1) for d in combinations(plist, l))))
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 09 2021
STATUS
approved