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%I #16 Jun 29 2019 01:41:58
%S 23,73,509,643,751,1093,1153,1481,1783,2029,6067,8011,8933,9613,16061,
%T 24763,30803,44203,64633,74521,82723,88003,94033,103171,106619,118669,
%U 126541,133321,154571,158293,163561,165883,179821,197339,202393,207643,225523,234733,264083,268003,284593,288661,324931
%N Primes whose base-9 representation is a square in base 10.
%C Primes in the sequence A267769.
%H Chai Wah Wu, <a href="/A267821/b267821.txt">Table of n, a(n) for n = 1..10000</a>
%e 73 in base 9 is 81, and 81 = 9^2 in base 10.
%t Select[Prime@ Range@ 28000, IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 9] &] (* _Michael De Vlieger_, Jan 24 2016 *)
%o (Python)
%o from sympy import isprime
%o A267821_list = [int(d,9) for d in (str(i**2) for i in range(1,10**6)) if max(d) < '9' and isprime(int(d,9))] # _Chai Wah Wu_, Feb 22 2016
%Y In other bases: A267817 - A267821, A241246, A267490.
%K nonn,base
%O 1,1
%A _Christopher Cormier_, Jan 20 2016
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