This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A267820 #16 Jun 29 2019 01:41:54 %S A267820 17,89,409,449,577,953,7649,12401,14593,23689,28393,29033,30689,36809, %T A267820 40153,46457,47969,54577,56393,59273,65033,72649,78713,92033,98953, %U A267820 106033,141353,146249,150209,169657,176489,199889,205433,221849,235273,238481,245033,258569,381841,394633,441193,529273 %N A267820 Primes whose base-6 representation is a square when read in base 10. %C A267820 Primes in the sequence A267766. %H A267820 Chai Wah Wu, <a href="/A267820/b267820.txt">Table of n, a(n) for n = 1..10000</a> %e A267820 17 in base 6 is 25, and 25 = 5^2 in base 10. %t A267820 Select[Prime@ Range@ 45000, IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 6] &] (* _Michael De Vlieger_, Jan 24 2016 *) %o A267820 (Python) %o A267820 from sympy import isprime %o A267820 A267820_list = [int(d,6) for d in (str(i**2) for i in range(1,10**6)) if max(d) < '6' and isprime(int(d,6))] # _Chai Wah Wu_, Feb 22 2016 %Y A267820 In other bases: A267817 - A267821, A241246, A267490. %K A267820 nonn,base %O A267820 1,1 %A A267820 _Christopher Cormier_, Jan 20 2016