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A368049
Perfect squares whose decimal expansion consists of k > 1 digits, k-1 of which are equal.
1
16, 25, 36, 49, 64, 81, 100, 121, 144, 225, 400, 441, 484, 676, 900, 1444, 10000, 40000, 44944, 90000, 1000000, 4000000, 9000000, 100000000, 400000000, 900000000, 10000000000, 40000000000, 90000000000, 1000000000000, 4000000000000, 9000000000000, 100000000000000
OFFSET
1,1
COMMENTS
The terms > 90000 are of one of the following three forms: 10^(2*j), 4*10^(2*j) or 9*10^(2*j) where j is an integer >= 3.
See Gica/Panaitopol link for proof of above comment. - Ray Chandler, Jan 16 2024
LINKS
Alexandru Gica and Laurențiu Panaitopol, On Oblath's Problem, J. Integer Seq., Vol. 6 (2003), article 03.3.5, 12 pp.
FORMULA
a(n) = 100*a(n-3) for n > 22. - Stefano Spezia, Dec 09 2023
CROSSREFS
Subsequence of A000290.
Sequence in context: A374934 A245371 A235717 * A319388 A291334 A175689
KEYWORD
nonn,base,easy
AUTHOR
José Hernández, Dec 09 2023
STATUS
approved