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
Examples
a(5) = 49 is a term because 49 = 7^2 = 1121_3.
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..3370 (terms 1..254 from Robert Israel)
Programs
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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 *)
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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