A001686 From a continued fraction. (Formerly M0893 N0338)

1, 1, 2, 3, 8, 51, 1538, 599871, 19417825808, 1573273218577214751, 124442887685693556895657990772138, 311057821480221188367831306672353513246409033360367599771

Offset

0,3

References

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

Table of n, a(n) for n=0..11.

V. C. Harris, Another proof of the infinitude of primes, Amer. Math. Monthly, 63 (1956), 711.

Formula

Denominator of continued fraction formed by terms of A001684. - Sean A. Irvine, Nov 13 2012

Example

For n=5, A001684(0..5) = 1, 1, 1, 1, 2, 6, and 1+1/(1+1/(1+1/(1+1/(2+1/6)))) = 83/51, so a(5)=51. - Michael B. Porter, Nov 29 2025

Crossrefs

Cf. A001684, Numerators are A001685.

Sequence in context: A103045 A126464 A041979 * A013205 A340486 A245384

Adjacent sequences: A001683 A001684 A001685 * A001687 A001688 A001689

Keyword

nonn

Author

N. J. A. Sloane

Extensions

a(11) from Sean A. Irvine, Nov 13 2012

Status

approved