OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,1).
FORMULA
a(n+7) = a(n) for n >= 21; (1,1,1,3,1,3,1 repeats). - Rick L. Shepherd, Apr 06 2006
G.f.: (x^27 + x^22 + 2*x^20 + x^16 + 2*x^15 + 4*x^13 + x^11 + 2*x^9 + 4*x^8 - 8*x^6 - 3*x^5 - 2*x^4 - 3*x^3 - 4*x^2 - 8*x - 1) / ((x - 1)*(x^6 + x^5 + x^4 + x^3 + x^2 + x + 1)). - Colin Barker, Feb 14 2014
EXAMPLE
The ratios are 1 (c), 9/8 (d), 5/4 (e), 4/3 (f), 3/2 (g), 5/3 (a), 15/8 (b); followed by these 7 numbers multiplied by successive powers of 2.
MATHEMATICA
Denominator[2^Floor[#/7]Rationalize[2^((-1+Floor[12(1+Mod[#, 7])/7])/12), 2^-6]]&/@Range[0, 70] (* Federico Provvedi, Feb 14 2014 *)
PadRight[{1, 8, 4, 3, 2, 3, 8, 1, 4, 2, 3, 1, 3, 4, 1, 2, 1, 3, 1, 3, 2}, 120, {1, 1, 1, 3, 1, 3, 1}] (* Harvey P. Dale, Nov 16 2020 *)
PROG
(PARI) r=[1, 9/8, 5/4, 4/3, 3/2, 5/3, 15/8]; for(n=0, 20, a=2^n*r; for(m=1, 7, print1(denominator(a[m]), ", "))) \\ Rick L. Shepherd, Apr 06 2006
(PARI) A071832(n)=denominator([1, 9/8, 5/4, 4/3, 3/2, 5/3, 15/8][n%7+1]*2^(n\7)) \\ M. F. Hasler, Jun 13 2012
CROSSREFS
KEYWORD
nonn,frac,easy,nice
AUTHOR
N. J. A. Sloane, Jun 10 2002
EXTENSIONS
More terms from Rick L. Shepherd, Apr 06 2006
STATUS
approved