A177842 Period 27: repeat 1, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 1, 81, 81, 9, 81, 81.

1, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 1, 81, 81, 9, 81, 81, 1, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 1, 81, 81, 9, 81, 81, 1, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 3, 81, 81, 9, 81, 81, 3, 81, 81, 1, 81, 81

Offset

0,2

Comments

The generating formula is a(n) = A061040(n+3) - 9*A061039(n+3). This is a member of the family of sequences with A000012(n) = A000290(n+1) -A005563(n+1), with period length 1, and A177499(n) = A061038(n+2) -4*A061037(n+2), with period length 4.

a(n) here has period length 3^3 and the general series of this family has period length k^k.

Links

Table of n, a(n) for n=0..77.

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1).

Formula

G.f.: ( -1 -81*x -3*x^9 -3*x^3 -81*x^4 -81*x^5 -9*x^6 -81*x^7 -81*x^8 -81*x^10 -3*x^12 -81*x^13 -81*x^14 -9*x^15 -81*x^16 -81*x^17 -3*x^18 -81*x^19 -81*x^20 -x^21 -81*x^22 -81*x^23 -9*x^24 -81*x^25 -81*x^26 -81*x^11 -81*x^2 ) / ( (x-1) *(1+x+x^2) *(1+x^3+x^6) *(1+x^9+x^18) ). - R. J. Mathar, Dec 09 2010

a(n) = a(n+27).

Prog

(PARI) a(n)=3^[0, 4, 4, 1, 4, 4, 2, 4, 4, 1, 4, 4, 1, 4, 4, 2, 4, 4, 1, 4, 4, 0, 4, 4, 2, 4, 4][n%27+1] \\ Charles R Greathouse IV, Jul 17 2016

Crossrefs

Sequence in context: A206150 A206143 A087410 * A075691 A055390 A186472

Adjacent sequences: A177839 A177840 A177841 * A177843 A177844 A177845

Keyword

nonn,easy

Author

Paul Curtz, May 14 2010

Status

approved