%I #18 Jul 29 2024 06:20:59
%S 1,21,85,151,227,341,1365,5461,14563,21845,87381,349525,932067,
%T 1398101,5592405,22369621,26512143,39768215,59652323,89478485,
%U 357913941,1431655765,3817748707,5726623061
%N Odd numbers whose Collatz trajectory is a Sidon sequence.
%C For more information see A375006.
%o (Python)
%o from itertools import count, islice
%o def A374527_gen(startvalue=1): # generator of terms >= startvalue
%o s = max(startvalue,1)
%o for n in count(s+(s&1^1),2):
%o t, a, c = [n], n, set()
%o while a > 1:
%o a = 3*a+1 if a&1 else a>>1
%o for p in t:
%o if (b:=p+a) in c:
%o break
%o c.add(b)
%o else:
%o t.append(a)
%o continue
%o break
%o else:
%o yield n
%o A374527_list = list(islice(A374527_gen(),10)) # _Chai Wah Wu_, Jul 27 2024
%Y Odd terms of A375006.
%K nonn,hard,more
%O 1,2
%A _Markus Sigg_ and _Hugo Pfoertner_, Jul 27 2024
%E a(23)-a(24) from _Chai Wah Wu_, Jul 29 2024