login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A329591
Decimal expansion of sqrt(34 + 2*sqrt(17))/4 = sqrt(8 + A222132)/2.
1
1, 6, 2, 4, 9, 2, 7, 1, 3, 7, 8, 1, 3, 3, 2, 5, 9, 4, 5, 1, 7, 0, 1, 1, 1, 6, 9, 1, 8, 7, 8, 8, 6, 6, 1, 0, 3, 8, 9, 2, 4, 5, 0, 0, 1, 4, 6, 6, 9, 2, 4, 9, 1, 6, 6, 8, 4, 5, 4, 7, 5, 9, 0, 8, 1, 5, 4, 1, 9, 2, 5, 9, 7, 3, 6, 7, 2, 4, 1, 2, 3, 8, 7, 4, 0, 2, 9, 6, 4, 2, 2, 9, 2, 3, 1, 6, 5, 3, 9
OFFSET
1,2
COMMENTS
The present cp := sqrt(34 + 2*sqrt(17))/4 is used, together with cm := sqrt(34 - 2*sqrt(17))/4 = sqrt(9 - A222132)/2 = A329592, for the roots of the integer polynomial P(4, x) := x^4 + x^3 - 6*x^2 - x + 1 which are x1 = 4 + cp - 2*cp^2, x2 = 4 - cp - 2*cp^2, x3 = 4 + cm - 2*cm^2, and x4 = 4 - cm - 2*cm^2. The approximate values of these zeros are 0.344150732, -2.905703544, 2.049481177, and -0.4879283650, respectively.
In the power basis of cp (denoted by (...)) and cm (denoted by [...]) the roots of P(4, x) are therefore: (4, +1, -2), (4, -1, -2), [4, +1, -2] and [4, -1, -2], respectively.
FORMULA
cp := sqrt(34 + 2*sqrt(17))/4 = sqrt(8 + w(17))/2, where w(17) = (1 - sqrt(17))/2 = A222132.
EXAMPLE
1.62492713781332594517011169187886610389245001466924916684547590815419...
MATHEMATICA
RealDigits[Sqrt[34 + 2*Sqrt[17]]/4, 10, 100][[1]] (* Amiram Eldar, Feb 17 2020 *)
CROSSREFS
Sequence in context: A135617 A019930 A169843 * A123139 A027599 A351297
KEYWORD
nonn,cons,easy
AUTHOR
Wolfdieter Lang, Feb 17 2020
STATUS
approved