A005485 Denominators of convergents to cube root of 7. (Formerly M4781)

1, 1, 11, 23, 379, 781, 1160, 5421, 12002, 17423, 377885, 395308, 1563809, 8214353, 9778162, 27770677, 37548839, 65319516, 168187871, 1915386097, 9745118356, 11660504453, 44726631715, 56387136168, 157500904051, 4308911545545, 17393147086231, 21702058631776

Offset

1,3

References

D. H. Lehmer, Guide to Tables in the Theory of Numbers. Bulletin No. 105, National Research Council, Washington, DC, 1941, p. 67.

P. Seeling, Verwandlung der irrationalen Groesse ... in einen Kettenbruch, Archiv. Math. Phys., 46 (1866), 80-120.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

Denominator[Convergents[7^(1/3), 40]] (* Vincenzo Librandi, Sep 08 2013 *)

Prog

(PARI) a(n)= contfracpnqn(contfrac(7^(1/3), n))[2, 1];  \\ Michel Marcus, Sep 07 2013

Crossrefs

Cf. A005482, A005484.

Sequence in context: A059327 A042005 A153318 * A041240 A193855 A295645

Adjacent sequences: A005482 A005483 A005484 * A005486 A005487 A005488

Keyword

nonn,frac

Author

N. J. A. Sloane.

Extensions

More terms from Herman P. Robinson.

More terms from Michel Marcus, Sep 07 2013

Inserted a(27) by Vincenzo Librandi, Sep 08 2013

Status

approved