A202907 Expand 1/(1 - (3/2)*x + (2/3)*x^4 - x^5) in powers of x, then multiply coefficient of x^n by 3^floor(n/4)*2^n to get integers.

1, 3, 9, 27, 211, 633, 1899, 5697, 52297, 156891, 470673, 1412019, 12675403, 38026209, 114078627, 342235881, 3081171505, 9243514515, 27730543545, 83191630635, 748691121283, 2246073363849, 6738220091547

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,0,0,211,0,0,0,7776).

Formula

From Chai Wah Wu, Aug 01 2020: (Start)

a(n) = 211*a(n-4) + 7776*a(n-8) for n > 7.

G.f.: -(3*x + 1)*(9*x^2 + 1)/(7776*x^8 + 211*x^4 - 1). (End)

Mathematica

Table[3^Floor[k/4]*2^k*SeriesCoefficient[ Series[1/(1 - (3/2)* x + (2/3) x^4 - x^5), {x, 0, 30}], k], {k, 0, 30}] (* Bagula *)
a[ n_] := 2^n 3^Quotient[ n, 4] SeriesCoefficient[ 1 / (1 - 3/2 x + 2/3 x^4 - x^5), {x, 0, n}] (* Michael Somos, Jan 27 2012 *)

Crossrefs

Cf. A167602, A167602, A117791, A107293, A204631, A185357.

Sequence in context: A028855 A299597 A143014 * A032261 A300981 A018924

Adjacent sequences: A202904 A202905 A202906 * A202908 A202909 A202910

Keyword

nonn,easy

Author

Roger L. Bagula, Jan 27 2012

Status

approved