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

1,1

Comments

Primes in the sequence A267769.

Links

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

Example

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

Mathematica

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

Prog

(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

Crossrefs

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

Sequence in context: A044161 A044542 A141945 * A237987 A157270 A102109

Adjacent sequences: A267818 A267819 A267820 * A267822 A267823 A267824

Keyword

nonn,base

Author

Christopher Cormier, Jan 20 2016

Status

approved