OFFSET
1,3
COMMENTS
Trivially includes powers of 81, since 81^k = 100..00_9 = 10^(2k) when read in base 10. Moreover, for any a(n) in the sequence, 81*a(n) is also in the sequence. One could call "primitive" the terms not of this form. These primitive terms include the subsequence 81^k + 2*9^k + 1 = (9^k+1)^2, k > 0, which yields A033934 when written in base 9.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[0, 5000], IntegerQ@ Sqrt@ FromDigits@ IntegerDigits[#, 9] &] (* Michael De Vlieger, Jan 24 2016 *)
PROG
(PARI) is(n, b=9, c=10)=issquare(subst(Pol(digits(n, b)), x, c))
(Python)
A267769_list = [int(s, 9) for s in (str(i**2) for i in range(10**6)) if max(s) < '9'] # Chai Wah Wu, Jan 20 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Jan 20 2016
STATUS
approved