A096230 Period 5: repeat [9, 7, 5, 3, 1].

9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1, 9, 7, 5, 3, 1

Offset: 1

Author

Odimar Fabeny, Jul 29 2004

Keywords

• nonn
• easy

Comments

Decimal expansion of 9 + 1/2 + 1/4 + 1/313 + 1/378244 + 1/2959729702407 = 975310/99999. - Bruno Berselli, Oct 02 2018

Links

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

Programs

Magma

&cat [[9, 7, 5, 3, 1]: n in [0..20]]; // Vincenzo Librandi, Jul 16 2015

Maple

map(op,[[9,7,5,3,1]$20]); # Robert Israel, Jul 16 2015

Mathematica

Table[2 Mod[-n, 5] + 1, {n, 105}] (* Robert G. Wilson v, Jul 31 2004 *)
PadRight[{}, 120, {9, 7, 5, 3, 1}] (* Harvey P. Dale, Dec 19 2012 *)

PARI

a(n) = 9 - 2*(n-1)%10; \\ Charles R Greathouse IV, Aug 25 2014

Formula

a(n) = 1 + 2*(-n mod 5). [From Wilson Mathematica program (2004)]

a(n) = 9 - (2*(n-1) mod 10). [From Greathouse PARI program (2014)]

From Robert Israel, Jul 16 2015: (Start)

G.f.: (9 + 7*x + 5*x^2 + 3*x^3 + x^4)/(1 - x^5).

a(n) = a(n-5).

a(n) + a((a(n)+1)/2) = 10. (End)

Extensions

Edited by N. J. A. Sloane and Robert G. Wilson v, Jul 31 2004