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A010907 Pisot sequence E(4,19), a(n) = floor( a(n-1)^2/a(n-2)+1/2 ). 2
4, 19, 90, 426, 2016, 9541, 45154, 213697, 1011348, 4786332, 22651920, 107203069, 507352048, 2401107571, 11363544486, 53779407822, 254517831936, 1204537747753, 5700626846950, 26978935702753 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

D. W. Boyd, Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory ( Kingston ON, 1991) 333-340, Oxford Sci. Publ., Oxford Univ. Press, New York, 1993.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

D. W. Boyd, Some integer sequences related to the Pisot sequences, Acta Arithmetica, 34 (1979), 295-305

FORMULA

Empirical G.f.: -(x^3+2*x^2+3*x+4)/(x^4+2*x^3+3*x^2+4*x-1). [Colin Barker, Nov 29 2012]

MATHEMATICA

PSE[a_, b_, n_]:=Join[{x=a, y=b}, Table[z=Floor[y^2/x+1/2]; x=y; y=z, {n}]]; A010907=PSE[4, 19, 20] (* Zak Seidov, Mar 24 2011 *)

CROSSREFS

Cf. A077922.

Sequence in context: A084155 A015530 A181880 * A229242 A087449 A004253

Adjacent sequences:  A010904 A010905 A010906 * A010908 A010909 A010910

KEYWORD

nonn

AUTHOR

Simon Plouffe

STATUS

approved

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Last modified December 22 05:04 EST 2014. Contains 252328 sequences.