A002361 Denominators of continued fraction convergents to fifth root of 2.

1, 6, 7, 20, 27, 47, 74, 269, 6799, 7068, 35071, 112281, 371914, 2715679, 141587222, 144302901, 430193024, 1434881973, 3299956970, 50934236523, 105168430016, 261271096555, 1150252816236, 18665316156331, 38480885128898, 288031512058617, 326512397187515

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• frac

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, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• 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 = 0..999

Crossrefs

Cf. A002362 (numerators), A002950, A005531.

Programs

Mathematica

Denominator[Convergents[2^(1/5), 30]] (* Harvey P. Dale, Apr 27 2012 *)

PARI

a(n)= contfracpnqn(contfrac(2^(1/5), n+1))[2, 1]; \\ Michel Marcus, Sep 07 2013

Extensions

More terms from Herman P. Robinson

Definition clarified and more terms from Harvey P. Dale, Apr 27 2012

Offset changed by Andrew Howroyd, Jul 05 2024