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A363428 Squares whose base-3 expansion has no 0. 2
1, 4, 16, 25, 49, 121, 400, 484, 1444, 1849, 3364, 5476, 10201, 10609, 10816, 12769, 17161, 19321, 19600, 155236, 169744, 274576, 286225, 344569, 346921, 450241, 502681, 863041, 885481, 984064, 1042441, 4008004, 4190209, 4596736, 7203856, 7263025, 7706176, 12752041, 14326225, 14341369, 23833924 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..3370 (terms 1..254 from Robert Israel)
EXAMPLE
a(5) = 49 is a term because 49 = 7^2 = 1121_3.
MAPLE
R1:= {1};
S1:= {1, 2};
for i from 1 to 15 do
S1:= map(t -> (3*t+1, 3*t+2), S1);
R1:= R1 union select(issqr, S1);
od:
Rl;
MATHEMATICA
Select[Range[5000]^2, ! MemberQ[IntegerDigits[#, 3], 0] &] (* Amiram Eldar, Jun 01 2023 *)
PROG
(Python)
from itertools import islice, count
from gmpy2 import digits
def A363428_gen(): # generator of terms
return filter(lambda n:'0' not in digits(n, 3), (n**2 for n in count(0)))
A363428_list = list(islice(A363428_gen(), 20)) # Chai Wah Wu, Jun 17 2023
CROSSREFS
Intersection of A000290 and A032924. Cf. A363408.
Sequence in context: A163095 A075576 A353295 * A295921 A338406 A351979
KEYWORD
nonn,base
AUTHOR
Robert Israel, Jun 01 2023
STATUS
approved

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Last modified April 18 04:31 EDT 2024. Contains 371767 sequences. (Running on oeis4.)