cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A236290 Decimal expansion of (sqrt(33) - 1) / 2.

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%I A236290 #17 Sep 05 2025 14:11:09
%S A236290 2,3,7,2,2,8,1,3,2,3,2,6,9,0,1,4,3,2,9,9,2,5,3,0,5,7,3,4,1,0,9,4,6,4,
%T A236290 6,5,9,1,1,0,1,3,2,2,2,8,9,9,1,3,9,6,1,8,3,8,4,9,9,3,8,7,3,5,2,8,2,9,
%U A236290 5,0,3,6,0,7,2,8,7,0,2,3,1,3,5,1,3,5,6,2,6,8,2,7,9,8,3,9,4
%N A236290 Decimal expansion of (sqrt(33) - 1) / 2.
%C A236290 Decimal expansion of sqrt(8 - sqrt(8 - sqrt(8 - sqrt(8 - ... )))).
%C A236290 The sequence with a(1) = 3 is decimal expansion of sqrt(8 + sqrt(8 + sqrt(8 + sqrt(8 + ... )))).
%C A236290 A quadratic integer with minimal polynomial x^2 + x - 8. - _Charles R Greathouse IV_, Apr 21 2016
%C A236290 Triangular root of 4. - _Stefano Spezia_, Sep 05 2025
%H A236290 Colin Foster, <a href="https://www.foster77.co.uk/Foster,%20Mathematical%20Spectrum,%20Triangular%20Roots.pdf">Triangular roots</a>, Applied Probability Trust, pp. 8-9, 2012.
%H A236290 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%F A236290 Equals A235162 - 1.
%e A236290 2.37228132326901432992530573410946465911013222899139618384993873528...
%p A236290 evalf((sqrt(33)-1)/2, 140);  # _Alois P. Heinz_, Sep 05 2025
%t A236290 RealDigits[(Sqrt[33] - 1)/2, 10, 130]
%o A236290 (PARI) (sqrt(33)-1)/2 \\ _Charles R Greathouse IV_, Apr 21 2016
%Y A236290 Cf. A010488, A235162.
%K A236290 nonn,cons,easy,changed
%O A236290 1,1
%A A236290 _Jaroslav Krizek_, Feb 07 2014