OFFSET
0,2
COMMENTS
A transformation of the Wonderful Demlo numbers (A002477).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
G. Villemin, Variations sur les carrés
Index entries for linear recurrences with constant coefficients, signature (111,-1110,1000).
FORMULA
From Chai Wah Wu, Apr 24 2017: (Start)
a(n) = 111*a(n-1) - 1110*a(n-2) + 1000*a(n-3) for n > 2.
G.f.: 4*x*(1 + 10*x)/((1 - x)*(1 - 10*x)*(1 - 100*x)).
(End)
a(n) = 4*(10^n - 1)^2/81. - Colin Barker, Apr 25 2017
EXAMPLE
a(2) = 22^2 = 484.
MATHEMATICA
LinearRecurrence[{111, -1110, 1000}, {0, 4, 484}, 30] (* Vincenzo Librandi, Apr 25 2017 *)
PROG
(Magma) I:=[0, 4, 484]; [n le 3 select I[n] else 111*Self(n-1)-1110*Self(n-2)+1000*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Apr 25 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Michael Taylor (michael.taylor(AT)vf.vodafone.co.uk), Sep 14 2002
STATUS
approved