OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
G.f.: x*(1 + 97*x + 64*x^2)/(1-x)^3. - Bruno Berselli, Aug 25 2011
From G. C. Greubel, Dec 28 2022: (Start)
a(2*n) = A016754(9*n).
a(2*n+1) = 4*A017222(n).
E.g.f.: (1 + 99*x + 81*x^2)*exp(x). (End)
MATHEMATICA
(9*Range[0, 40] +1)^2 (* G. C. Greubel, Dec 28 2022 *)
LinearRecurrence[{3, -3, 1}, {1, 100, 361}, 50] (* Harvey P. Dale, Feb 25 2024 *)
PROG
(Magma) [(9*n+1)^2: n in [0..40]]; // Vincenzo Librandi, Aug 25 2011
(PARI) a(n)=(9*n+1)^2 \\ Charles R Greathouse IV, Jun 17 2017
(SageMath) [(9*n+1)^2 for n in range(41)] # G. C. Greubel, Dec 28 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved