[go: up one dir, main page]

login
A098207
a(n) is the square of near-repdigit number A033175(n).
1
1, 961, 109561, 11095561, 1110955561, 111109555561, 11111095555561, 1111110955555561, 111111109555555561, 11111111095555555561, 1111111110955555555561, 111111111109555555555561
OFFSET
0,2
COMMENTS
While repunit-squares are palindromic, squares of near repdigits provide other curious digit-patterns.
FORMULA
a(n) = A033175(n)^2.
From Chai Wah Wu, Nov 09 2018: (Start)
a(n) = 111*a(n-1) - 1110*a(n-2) + 1000*a(n-3) for n > 2.
G.f.: (-4000*x^2 - 850*x - 1)/((x - 1)*(10*x - 1)*(100*x - 1)). (End)
CROSSREFS
Sequence in context: A274120 A063797 A231761 * A304315 A158414 A031740
KEYWORD
nonn,base,easy
AUTHOR
Labos Elemer, Oct 20 2004
STATUS
approved