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A368341
Fixed points of A368207.
1
0, 1, 2, 8, 9, 32, 128, 238, 512, 1012, 2048, 8192, 15070, 21658, 32768, 131072, 383548, 391612, 524288
OFFSET
1,3
COMMENTS
Numbers k such that A368207(k)=k.
Conjecture: 2^(2k+1) for k>=0 (A004171) are terms.
PROG
(Python)
from itertools import count, islice
from sympy import divisors
def A368341_gen(startvalue=0): # generator of terms >= startvalue
for n in count(max(startvalue, 0)):
c = 0
for d2 in divisors(n):
if d2**2 > n:
break
c += (d2<<2)-2 if d2**2<n else (d2<<1)-1
if c>n:
break
if c<=n:
for wx in range(1, (n>>1)+1):
for d1 in divisors(wx):
if d1**2 > wx:
break
for d2 in divisors(m:=n-wx):
if d2**2 > m:
break
if wx < d1*d2:
k = 1
if d1**2 != wx:
k <<=1
if d2**2 != m:
k <<=1
c+=k
if c>n:
break
if c==n:
yield n
A368341_list = list(islice(A368341_gen(), 10))
CROSSREFS
Sequence in context: A075644 A088825 A337706 * A369649 A181887 A221049
KEYWORD
nonn,more
AUTHOR
Chai Wah Wu, Dec 21 2023
EXTENSIONS
a(17)-a(19) from Chai Wah Wu, Dec 22 2023
STATUS
approved