A128271 a(n) = the denominator of b(n): {b(n)} is such that the continued fraction (of rational terms) [b(1);b(2),...,b(n)] equals the n-th prime, for every positive integer n.

1, 1, 2, 1, 4, 1, 16, 1, 64, 3, 32, 27, 256, 27, 1024, 243, 1024, 243, 512, 27, 1024, 27, 1024, 243, 8192, 243, 16384, 243, 4096, 243, 7168, 81, 12544, 243, 15680, 27, 39200, 27, 62720, 243, 313600, 243, 1568000, 27, 31360000, 27, 17920000, 27, 31360000, 27

Offset

1,3

Links

Diana Mecum, Table of n, a(n) for n = 1..500

Example

b(n): 2, 1, -3/2, 4, -3/4, 12, -3/16,...
The 4th prime, 7, equals [b(1);b(2),b(3),b(4)] = 2 +1/(1 +1/(-3/2 +1/4)).
The 5th prime, 11, equals [b(1);b(2),b(3),b(4),b(5)] = 2 +1/(1 +1/(-3/2 +1/(4 -4/3))).

Crossrefs

Cf. A128270.

Sequence in context: A145930 A145762 A024539 * A092891 A229484 A080212

Adjacent sequences: A128268 A128269 A128270 * A128272 A128273 A128274

Keyword

frac,nonn

Author

Leroy Quet, Feb 22 2007

Extensions

More terms from Diana L. Mecum, Jun 24 2007

Status

approved