A031432 - OEIS

A031432

Least term in period of continued fraction for sqrt(n) is 8.

17, 66, 147, 260, 405, 582, 791, 1032, 1305, 1610, 1690, 1947, 2316, 2717, 3150, 3615, 4112, 4641, 4778, 5202, 5795, 6420, 7077, 7413, 7766, 8487, 9240, 10025, 10842, 11691, 12572, 13244, 13485, 14430, 14671, 15407, 16416, 16673, 17457

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OFFSET

1,1

COMMENTS

16*m^2 + m for m >= 1 are terms of this sequence (see comment in A031742). The first term that is not of this form is a(11) = 1690. - Chai Wah Wu, Jun 19 2016

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 200 from Vincenzo Librandi)

MATHEMATICA

Select[Range[20000], !IntegerQ[Sqrt[#]] && Min[ContinuedFraction[Sqrt[#]][[2]]] == 8&] (* Vincenzo Librandi, Feb 07 2012 *)

CROSSREFS

Sequence in context: A044536 A115295 A065011 * A157474 A024215 A095071

Adjacent sequences: A031429 A031430 A031431 * A031433 A031434 A031435

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved