A363428 Squares whose base-3 expansion has no 0.

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

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

Adjacent sequences: A363425 A363426 A363427 * A363429 A363430 A363431

Keyword

nonn,base

Author

Robert Israel, Jun 01 2023

Status

approved