A267821 Primes whose base-9 representation is a square in base 10.

23, 73, 509, 643, 751, 1093, 1153, 1481, 1783, 2029, 6067, 8011, 8933, 9613, 16061, 24763, 30803, 44203, 64633, 74521, 82723, 88003, 94033, 103171, 106619, 118669, 126541, 133321, 154571, 158293, 163561, 165883, 179821, 197339, 202393, 207643, 225523, 234733, 264083, 268003, 284593, 288661, 324931

Offset: 1

Author

Christopher Cormier, Jan 20 2016

Keywords

• nonn
• base

Comments

Primes in the sequence A267769.

Examples

			73 in base 9 is 81, and 81 = 9^2 in base 10.
		

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..10000

Crossrefs

In other bases: A267817 - A267821, A241246, A267490.

Programs

Mathematica

Select[Prime@ Range@ 28000, IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 9] &] (* Michael De Vlieger, Jan 24 2016 *)

Python

from sympy import isprime
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