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A006458
Number of elements in Z[ omega ] whose 'smallest algorithm' is <= n, where omega^2 = -omega - 1.
(Formerly M4399)
3
1, 7, 31, 115, 391, 1267, 3979, 12271, 37423, 113371, 342091, 1029799, 3095671, 9298147, 27914179, 83777503, 251394415, 754292827, 2263072411, 6789560407, 20369288455, 61108939795, 183328720435, 549989524879, 1649974525855, 4949934107083, 14849820951115
OFFSET
0,2
COMMENTS
omega is a primitive third root of unity. - Joerg Arndt, Apr 29 2021
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009.
Simon Plouffe, 1031 Generating Functions, Appendix to Thesis, Montreal, 1992.
P. Samuel, About Euclidean rings, J. Alg., 19 (1971), 282-301.
FORMULA
a(n+6) - 5*a(n+5) + 5*a(n+4) + 5*a(n+3) - 4*a(n+2) - 8*a(n+1) + 6*a(n) = 0.
G.f.: (x*(6*x^4+2*x^3+x+2)+1)/((x-1)^2*(3*x-1)*(2*x^2*(x+1)-1)). - Harvey P. Dale, Mar 03 2012
MAPLE
A006458:=(1+2*z+z**2+2*z**4+6*z**5)/(3*z-1)/(2*z**3+2*z**2-1)/(z-1)**2; # Conjectured by Simon Plouffe in his 1992 dissertation
MATHEMATICA
LinearRecurrence[{5, -5, -5, 4, 8, -6}, {1, 7, 31, 115, 391, 1267}, 40] (* Harvey P. Dale, Mar 03 2012 *)
CROSSREFS
Sequence in context: A097786 A350498 A197649 * A091344 A032197 A114289
KEYWORD
nonn,easy,nice
AUTHOR
H. W. Lenstra, Jr
EXTENSIONS
Corrected by T. D. Noe, Nov 08 2006
More terms from Harvey P. Dale, Mar 03 2012
Name corrected by Joerg Arndt, Apr 29 2021
STATUS
approved