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A014772
Squares of even hexagonal numbers.
0
36, 784, 4356, 14400, 36100, 76176, 142884, 246016, 396900, 608400, 894916, 1272384, 1758276, 2371600, 3132900, 4064256, 5189284, 6533136, 8122500, 9985600, 12152196, 14653584, 17522596, 20793600, 24502500, 28686736
OFFSET
1,1
FORMULA
G.f.: 4*x*(9+151*x+199*x^2+25*x^3)/(1-x)^5 [From Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009]
a(1)=36, a(2)=784, a(3)=4356, a(4)=14400, a(5)=36100, a(n)=5*a(n-1)- 10*a(n-2)+ 10*a(n-3)-5*a(n-4)+a(n-5) [From Harvey P. Dale, May 11 2012]
MATHEMATICA
Take[Table[n(2n-1), {n, 60}], {2, -1, 2}]^2 (* or *) LinearRecurrence[ {5, -10, 10, -5, 1}, {36, 784, 4356, 14400, 36100}, 30](* Harvey P. Dale, May 11 2012 *)
CROSSREFS
Cf. A014635.
Sequence in context: A280123 A004338 A228331 * A110206 A133051 A215605
KEYWORD
nonn,easy
EXTENSIONS
G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.
More terms from Erich Friedman.
STATUS
approved