A152258 a(n) = ((3^n - 1)*(3^n + 1))^2/2^(7 - (n mod 2)).

0, 1, 50, 8281, 336200, 54479161, 2206472450, 357449732641, 14476719552800, 2345228664408721, 94981761344401250, 15387045345638267401, 623175336533653521800, 100954404519087336988681, 4088653383025896747098450, 662361848050246745812972561

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..500

Index entries for linear recurrences with constant coefficients, signature (0,6643,0,-538083,0,531441).

Formula

a(n) = ((3^n - 1)*(3^n + 1))^2 / 2^(7 - (n mod 2)).

a(n) = 6643*a(n-2) - 538083*a(n-4) + 531441*a(n-6). - R. J. Mathar, Dec 04 2008

Mathematica

Table[(9^n-1)^2/2^(7-Mod[n, 2]), {n, 0, 30}]

Prog

(Magma) 2^((n mod 2) -7)*(9^n-1)^2: n in [0..40]]; // G. C. Greubel, May 22 2023
(SageMath) [(9^n-1)^2//2^(7-(n%2)) for n in range(41)] # G. C. Greubel, May 22 2023

Crossrefs

Cf. A002452, A003462.

Sequence in context: A301992 A229753 A276102 * A364511 A203097 A028465

Adjacent sequences: A152255 A152256 A152257 * A152259 A152260 A152261

Keyword

nonn

Author

Roger L. Bagula, Dec 01 2008

Status

approved