A065005 Integers for which the periodic part of the continued fraction for the square root of n begins with 2.

2, 6, 12, 19, 20, 29, 30, 41, 42, 54, 55, 56, 70, 71, 72, 88, 89, 90, 107, 108, 109, 110, 129, 130, 131, 132, 153, 154, 155, 156, 178, 179, 180, 181, 182, 206, 207, 208, 209, 210, 236, 237, 238, 239, 240, 267, 268, 269, 270, 271, 272, 301, 302, 303, 304, 305

Offset

1,1

Links

Table of n, a(n) for n=1..56.

Example

The continued fraction for the square root of 12 is 3, {2, 6}.

Mathematica

Select[ Range[500], First[ Last[ ContinuedFraction[ Sqrt[ # ]]]] == 2 & ]

Crossrefs

Sequence in context: A178480 A053660 A104969 * A299016 A347472 A340663

Adjacent sequences: A065002 A065003 A065004 * A065006 A065007 A065008

Keyword

easy,nonn

Author

Robert G. Wilson v, Nov 01 2001

Status

approved