A031426 - OEIS

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A031426

Least term in period of continued fraction for sqrt(n) is 2.

2, 6, 12, 20, 28, 30, 41, 42, 55, 56, 72, 89, 90, 110, 126, 130, 131, 132, 155, 156, 177, 180, 182, 209, 210, 240, 269, 270, 272, 299, 303, 305, 306, 342, 368, 372, 377, 380, 418, 420, 451, 458, 462, 497, 504, 505, 506, 552, 590, 600, 646, 648

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 1000 from Vincenzo Librandi)

MATHEMATICA

Select[Range[600], !IntegerQ[Sqrt[#]] && Min[ContinuedFraction[Sqrt[#]][[2]]] == 2&] (* Vincenzo Librandi, Feb 06 2012 *)

CROSSREFS

Sequence in context: A355331 A270878 A120344 * A258633 A244362 A175967

Adjacent sequences: A031423 A031424 A031425 * A031427 A031428 A031429

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved