A160390 -id:A160390 - cp's OEIS frontend

A134451 Ternary digital root of n.

0, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2

Offset: 0

Reinhard Zumkeller, Oct 27 2007

Continued fraction expansion of sqrt(3) - 1. - N. J. A. Sloane, Dec 17 2007. Cf. A040001, A048878/A002530.
Minimum number of terms required to express n as a sum of odd numbers.
Shadow transform of even numbers A005843. - Michel Marcus, Jun 06 2013
From Jianing Song, Nov 01 2022: (Start)
For n > 0, a(n) is the minimal gap of distinct numbers coprime to n. Proof: denote the minimal gap by b(n). For odd n we have A058026(n) > 0, hence b(n) = 1. For even n, since 1 and -1 are both coprime to n we have b(n) <= 2, and that b(n) >= 2 is obvious.
The maximal gap is given by A048669. (End)

			n=42: A007089(42) = '1120', A053735(42) = 1+1+2+0 = 4,
A007089(4)='11', A053735(4)=1+1=2: therefore a(42) = 2.
0.732050807568877293527446341... = 0 + 1/(1 + 1/(2 + 1/(1 + 1/(2 + ...)))). - _Harry J. Smith_, May 31 2009

Harry J. Smith, Table of n, a(n) for n = 0..20000
Lorenz Halbeisen and Norbert Hungerbuehler, Number theoretic aspects of a combinatorial function, Notes on Number Theory and Discrete Mathematics 5(4) (1999), 138-150; see Definition 7 for the shadow transform.
N. J. A. Sloane, Transforms.
Eric Weisstein's World of Mathematics, Digital Root.
Eric Weisstein's World of Mathematics, Ternary.

Cf. A000010, A055034, A134452, A160390 (decimal expansion).
Apart from a(0) the same as A040001.
Related base-3 sequences: A053735, A134451, A230641, A230642, A230643, A230853, A230854, A230855, A230856, A230639, A230640, A010063 (trajectory of 1).

a134451 = until (< 3) a053735
-- Reinhard Zumkeller, May 12 2011

A134451:=n->((n+1) mod 2)+2*signum(n)-1; seq(A134451(n), n=0..100); # Wesley Ivan Hurt, Dec 06 2013

Table[Mod[n + 1, 2] + 2 Sign[n] - 1, {n, 0, 100}] (* Wesley Ivan Hurt, Dec 06 2013 *)

a(n) = if(!n, 0, 2 - n%2) \\ Andrew Howroyd, Dec 08 2024

a(n) = n if n <= 2, otherwise a(A053735(n)).
a(A005408(n)) = 1; a(A005843(n)) = 2 for n>0;
a(n) = 0 if n=0, otherwise A000034(n-1).
a(n) = ((n+1) mod 2) + 2*sign(n) - 1. - Wesley Ivan Hurt, Dec 06 2013
Multiplicative with a(2^e) = 2, a(p^e) = 1 for odd prime p. - Andrew Howroyd, Aug 06 2018
a(0) = A055034(1) / A000010(1), a(n) = A000010(n+1) / A055034(n+1), n>1. - Torlach Rush, Oct 29 2019
Dirichlet g.f.: zeta(s)*(1+1/2^s). - Amiram Eldar, Jan 01 2023

A048788 a(2n+1) = a(2n) + a(2n-1), a(2n) = 2*a(2n-1) + a(2n-2); a(n) = n for n = 0, 1.

Original entry on oeis.org

0, 1, 2, 3, 8, 11, 30, 41, 112, 153, 418, 571, 1560, 2131, 5822, 7953, 21728, 29681, 81090, 110771, 302632, 413403, 1129438, 1542841, 4215120, 5757961, 15731042, 21489003, 58709048, 80198051, 219105150, 299303201, 817711552, 1117014753

Offset: 0

Robin Trew (trew(AT)hcs.harvard.edu), Dec 11 1999

Numerators of continued fraction convergents to sqrt(3) - 1 (A160390). See A002530 for denominators. - N. J. A. Sloane, Dec 17 2007
Convergents are 1, 2/3, 3/4, 8/11, 11/15, 30/41, 41/56, 112/153, ... - Clark Kimberling, Sep 21 2013
A strong divisibility sequence, that is gcd(a(n),a(m)) = a(gcd(n,m)) for all positive integers n and m. - Peter Bala, Jun 06 2014
From Sarah-Marie Belcastro, Feb 15 2022: (Start)
a(n) is also the number of perfect matchings of an edge-labeled 2 X (n-1) Mobius band grid graph, or equivalently the number of domino tilings of a 2 X (n-1) Mobius band grid. (The twist is on the length-n side.)
a(n) is also the output of Lu and Wu's formula for the number of perfect matchings of an m X n Mobius band grid, specialized to m = 2 with the twist on the length-n side.
2*a(n) is the number of perfect matchings of an edge-labeled 2 X (n-1) projective planar grid graph, or equivalently the number of domino tilings of a 2 X (n-1) projective planar grid. (End)

Russell Lyons, A bird's-eye view of uniform spanning trees and forests, in Microsurveys in Discrete Probability, AMS, 1998.

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Peter Bala, Notes on 2-periodic continued fractions and Lehmer sequences
Sarah-Marie Belcastro, Domino Tilings of 2 X n Grids (or Perfect Matchings of Grid Graphs) on Surfaces, J. Integer Seq. 26 (2023), Article 23.5.6.
Marcia Edson, Scott Lewis and Omer Yayenie, The k-periodic Fibonacci sequence and an extended Binet's formula, INTEGERS 11 (2011) #A32.
W. T. Lu and F. Y. Wu, Close-packed dimers on nonorientable surfaces, Physics Letters A, 293 (2002), 235-246.
D. Panario, M. Sahin, and Q. Wang, A family of Fibonacci-like conditional sequences, INTEGERS, Vol. 13, 2013, #A78.
J. L. Ramirez and F. Sirvent, A q-Analogue of the Bi-Periodic Fibonacci Sequence, J. Int. Seq. 19 (2016) # 16.4.6, t_n at a=2, b=1.
Index to divisibility sequences
Index entries for linear recurrences with constant coefficients, signature (0,4,0,-1).

Cf. A002530, A002531.

Bisections are A001835 and A052530.

a:=[0,1,2,3];; for n in [5..40] do a[n]:=4a[n-1]-a[n-2]; od; a; # G. C. Greubel, Dec 23 2019

I:=[0,1,2,3]; [n le 4 select I[n] else 4*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 10 2013

seq( simplify( `if`(`mod`(n,2)=0, 2*ChebyshevU((n-2)/2, 2), ChebyshevU((n-1)/2, 2) - ChebyshevU((n-3)/2, 2)) ), n=0..40); # G. C. Greubel, Dec 23 2019

Numerator[NestList[(2/(2 + #))&, 0, 40]] (* Vladimir Joseph Stephan Orlovsky, Apr 13 2010 *)
CoefficientList[Series[x(1+2x-x^2)/(1-4x^2+x^4), {x, 0, 40}], x] (* Vincenzo Librandi, Dec 10 2013 *)
a0[n_]:= ((3+Sqrt[3])*(2-Sqrt[3])^n-((-3+Sqrt[3])*(2+Sqrt[3])^n))/6 // Simplify
a1[n_]:= 2*Sum[a0[i], {i, 1, n}]
Flatten[MapIndexed[{a1[#-1],a0[#]}&,Range[20]]] (* Gerry Martens, Jul 10 2015 *)
Round@Table[With[{r=1+Sqrt[2], s=1+Sqrt[3]}, ((r + (-1)^n/r) s^n/2^(n/2) - (1/r + (-1)^n r) 2^(n/2)/s^n) Sqrt[6]/12], {n, 0, 20}] (* or *) LinearRecurrence[ {0,4,0,-1}, {0,1,2,3}, 40] (* Vladimir Reshetnikov, May 11 2016 *)
Table[If[EvenQ[n], 2*ChebyshevU[(n-2)/2, 2], ChebyshevU[(n-1)/2, 2] - ChebyshevU[(n-3)/2, 2]], {n, 0, 40}] (* G. C. Greubel, Dec 23 2019 *)

main(size)=v=vector(size); v[1]=0;v[2]=1;v[3]=2;v[4]=3;for(i=5, size, v[i]=4*v[i-2] - v[i-4]); v; \\ Anders Hellström, Jul 11 2015

a=vector(50); a[1]=1; a[2]=2; for(n=3, #a, if(n%2==1, a[n]=a[n-1]+a[n-2], a[n]=2*a[n-1]+a[n-2])); concat(0, a) \\ Colin Barker, Jan 30 2016

a(n)=([0,1,0,0;0,0,1,0;0,0,0,1;-1,0,4,0]^n*[0;1;2;3])[1,1] \\ Charles R Greathouse IV, Mar 16 2017

apply( {A048788(n)=imag((2+quadgen(12))^(n\/2)*if(bittest(n, 0), quadgen(12)-1, 2))}, [0..30]) \\ M. F. Hasler, Nov 04 2019

{a(n) = my(s=1,m=n); if(n<0,s=-(-1)^n; m=-n); polcoeff(x*(1+2*x-x^2)/(1-4*x^2+x^4) + x*O(x^m), m)*s}; /* Michael Somos, Sep 17 2020 */

@CachedFunction
def a(n):
    if (mod(n,2)==0): return 2*chebyshev_U((n-2)/2, 2)
    else: return chebyshev_U((n-1)/2, 2) - chebyshev_U((n-3)/2, 2)
[a(n) for n in (0..40)] # G. C. Greubel, Dec 23 2019

G.f.: x*(1+2*x-x^2)/(1-4*x^2+x^4). - Paul Barry, Sep 18 2009
a(n) = 4*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 10 2013
a(2*n-1) = A001835(n); a(2*n) = 2*A001353(n). - Peter Bala, Jun 06 2014
From Gerry Martens, Jul 11 2015: (Start)
Interspersion of 2 sequences [a1(n-1),a0(n)] for n>0:
a0(n) = ((3+sqrt(3))*(2-sqrt(3))^n-((-3+sqrt(3))*(2+sqrt(3))^n))/6.
a1(n) = 2*Sum_{i=1..n} a0(i). (End)
a(n) = ((r + (-1)^n/r)*s^n/2^(n/2) - (1/r + (-1)^n*r)*2^(n/2)/s^n)*sqrt(6)/12, where r = 1 + sqrt(2), s = 1 + sqrt(3). - Vladimir Reshetnikov, May 11 2016
a(n) = 2*ChebyshevU(n-1, 2) if n is even and ChebyshevU(n, 2) - ChebyshevU(n-1, 2) if n in odd. - G. C. Greubel, Dec 23 2019
a(n) = -(-1)^n*a(-n) for all n in Z. - Michael Somos, Sep 17 2020

Denominator of g.f. corrected by Paul Barry, Sep 18 2009

Incorrect g.f. deleted by Colin Barker, Aug 10 2012

A165663 Decimal expansion of 3 + sqrt(3).

Original entry on oeis.org

4, 7, 3, 2, 0, 5, 0, 8, 0, 7, 5, 6, 8, 8, 7, 7, 2, 9, 3, 5, 2, 7, 4, 4, 6, 3, 4, 1, 5, 0, 5, 8, 7, 2, 3, 6, 6, 9, 4, 2, 8, 0, 5, 2, 5, 3, 8, 1, 0, 3, 8, 0, 6, 2, 8, 0, 5, 5, 8, 0, 6, 9, 7, 9, 4, 5, 1, 9, 3, 3, 0, 1, 6, 9, 0, 8, 8, 0, 0, 0, 3, 7, 0, 8, 1, 1, 4, 6, 1, 8, 6, 7, 5, 7, 2, 4, 8, 5, 7, 5, 6, 7, 5, 6, 2

Offset: 1

Jonathan Vos Post, Sep 24 2009

Arises as an upper limit of indices of subfactors in the extended Haagerup planar algebra (see Bigelow et al.)
Perimeter of a 30-60-90 triangle with shortest side equal to 1. - Wesley Ivan Hurt, Apr 09 2016
Surface area of an elongated triangular pyramid (Johnson solid J_7) with unit edges. - Paolo Xausa, Aug 02 2025

			4.732050807568877293527446341505872366942805253810380628...

G. C. Greubel, Table of n, a(n) for n = 1..10000
Stephen Bigelow, Scott Morrison, Emily Peters, and Noah Snyder, Constructing the extended Haagerup planar algebra, arXiv:0909.4099 [math.OA], 2009-2011.
Wikipedia, Elongated triangular pyramid.
Index entries for algebraic numbers, degree 2

Cf. A002194, A019973, A090388, A160390.

SetDefaultRealField(RealField(100)); 3 + Sqrt(3); // G. C. Greubel, Nov 20 2018

Digits:=100: evalf(3+sqrt(3)); # Wesley Ivan Hurt, Apr 09 2016

RealDigits[3 + Sqrt[3], 10, 100][[1]] (* Wesley Ivan Hurt, Apr 09 2016 *)

default(realprecision, 100); 3 + sqrt(3) \\ G. C. Greubel, Nov 20 2018

numerical_approx(3+sqrt(3), digits=100) # G. C. Greubel, Nov 20 2018

Equals 4 + A160390 = 1 + A019973 = 2 + A090388 = 3 + A002194. - R. J. Mathar, Sep 27 2009

A286389 a(0) = 0; a(n) = n - a(floor(a(n-1)/2)).

Original entry on oeis.org

0, 1, 2, 2, 3, 4, 4, 5, 6, 7, 8, 8, 9, 10, 10, 11, 12, 13, 14, 14, 15, 16, 16, 17, 18, 18, 19, 20, 20, 21, 22, 23, 24, 24, 25, 26, 26, 27, 28, 29, 30, 30, 31, 32, 32, 33, 34, 34, 35, 36, 36, 37, 38, 39, 40, 40, 41, 42, 42, 43, 44, 45, 46, 46, 47, 48, 48, 49, 50, 51, 52, 52, 53, 54, 54, 55, 56, 57, 58, 58

Offset: 0

Ilya Gutkovskiy, May 24 2017

A variation on Hofstadter's G-sequence.
Conjecture: partial sums of A285431 (verified for n <= 400). - Sean A. Irvine, Jul 20 2022
The conjecture has been verified for n <= 50000. - Michel Dekking, Jul 06 2023
Irvine's conjecture is now proven using the Walnut theorem prover. - Jeffrey Shallit, Oct 21 2023

Anton Mosunov, Table of n, a(n) for n = 0..400
Jeffrey Shallit, Proof of Irvine's conjecture via mechanized guessing, arXiv preprint arXiv:2310.14252 [math.CO], October 22 2023.
Index entries for Hofstadter-type sequences

Cf. A005206, A138466, A160390.

a[0] = 0; a[n_] := a[n] = n - a[Floor[a[n - 1]/2]]; Array[a, 80, 0]

a(n)=if(n>0,return(n-a(floor(a(n-1)/2))));return(0); \\ Anton Mosunov, May 26 2017

Conjecture: a(n) ~ c*n, where c = sqrt(3) - 1 = 0.732050807...
From Michel Dekking, Jul 06 2023: (Start)
This conjecture is implied by the conjecture in the COMMENTS, by a simple application of the Perron-Frobenius Theorem.
The vector (1, 1 + sqrt(3)) is a right eigenvector of the incidence matrix of the morphism 0->11, 1->110. Therefore the frequency of 1 in A285431 is equal to sqrt(3) - 1. So if the conjecture in the COMMENTS is true, then this implies that a(n)/n converges to sqrt(3) - 1. (End)

A138466 a(1)=1; for n >= 2, a(n) = n - floor((1/2)*a(a(n-1))).

Original entry on oeis.org

1, 2, 2, 3, 4, 5, 5, 6, 7, 8, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 16, 16, 17, 18, 19, 19, 20, 21, 21, 22, 23, 24, 24, 25, 26, 27, 27, 28, 29, 30, 30, 31, 32, 32, 33, 34, 35, 35, 36, 37, 38, 38, 39, 40, 40, 41, 42, 43, 43, 44, 45, 46, 46, 47, 48, 49, 49, 50, 51, 51, 52, 53, 54

Offset: 1

Benoit Cloitre, May 09 2008

Michel Dekking, Proof by Benoit Cloitre

Cf. A005206, A138467, A160390.

Floor[(Sqrt[3] - 1)*(Range[100] + 1)] (* Wesley Ivan Hurt, Jan 20 2024 *)

PARI
```
a(n)=floor((sqrt(3)-1)*(n+1))
```

For n >= 1, a(n) = floor((sqrt(3)-1)*(n+1)).

A270397 Denominators of r-Egyptian fraction expansion for sqrt(3) - 1, where r(k) = 1/Fibonacci(k+1).

Original entry on oeis.org

2, 3, 6, 21, 411, 120274, 10572781147, 74407087111123560666, 5372512080606517833291366730287672914459, 41169436260792910821230360026041473906108740980452651576082359437785122898819171

Offset: 1

Clark Kimberling, Mar 22 2016

Suppose that r is a sequence of rational numbers r(k) <= 1 for k >= 1, and that x is an irrational number in (0,1). Let f(0) = x, n(k) = floor(r(k)/f(k-1)), and f(k) = f(k-1) - r(k)/n(k). Then x = r(1)/n(1) + r(2)/n(2) + r(3)/n(3) + ..., the r-Egyptian fraction for x.

See A269993 for a guide to related sequences.

			sqrt(3) - 1 = 1/2 + 1/(2*3) + 1/(3*6) + 1/(5*21) + ...

Clark Kimberling, Table of n, a(n) for n = 1..13
Eric Weisstein's World of Mathematics, Egyptian Fraction.
Index entries for sequences related to Egyptian fractions

Cf. A269993, A000045, A160390.

r[k_] := 1/Fibonacci[k+1]; f[x_, 0] = x; z = 10;
n[x_, k_] := n[x, k] = Ceiling[r[k]/f[x, k - 1]]
f[x_, k_] := f[x, k] = f[x, k - 1] - r[k]/n[x, k]
x = Sqrt[3] - 1; Table[n[x, k], {k, 1, z}]

r(k) = 1/fibonacci(k+1);
f(k,x) = if (k==0, x, f(k-1, x) - r(k)/a(k, x););
a(k, x=sqrt(3)-1) = ceil(r(k)/f(k-1, x)); \\ Michel Marcus, Mar 22 2016

A270520 Denominators of r-Egyptian fraction expansion for sqrt(3) - 1, where r(k) = 1/k!.

Original entry on oeis.org

2, 3, 3, 5, 6, 14, 28, 352, 18574, 44518346, 400826881311158, 25342673472297507115832358714, 62130292590921086469117151395751018383242940308998211770

Offset: 1

Clark Kimberling, Mar 30 2016

Suppose that r is a sequence of rational numbers r(k) <= 1 for k >= 1, and that x is an irrational number in (0,1). Let f(0) = x, n(k) = floor(r(k)/f(k-1)), and f(k) = f(k-1) - r(k)/n(k). Then x = r(1)/n(1) + r(2)/n(2) + r(3)/n(3) + ..., the r-Egyptian fraction for x.

See A269993 for a guide to related sequences.

			sqrt(3) - 1 = 1/(1*2) + 1/(2*3) + 1/(6*3) + 1/(24*5) + ...

Clark Kimberling, Table of n, a(n) for n = 1..20
Eric Weisstein's World of Mathematics, Egyptian Fraction
Index entries for sequences related to Egyptian fractions

Cf. A269993, A000142, A160390.

r[k_] := 1/k!; f[x_, 0] = x; z = 10;
n[x_, k_] := n[x, k] = Ceiling[r[k]/f[x, k - 1]]
f[x_, k_] := f[x, k] = f[x, k - 1] - r[k]/n[x, k]
x = Sqrt[3] - 1; Table[n[x, k], {k, 1, z}]

r(k) = 1/k!;
f(k,x) = if (k==0, x, f(k-1, x) - r(k)/a(k, x););
a(k, x=sqrt(3)-1) = ceil(r(k)/f(k-1, x)); \\ Michel Marcus, Mar 31 2016

A270549 Denominators of r-Egyptian fraction expansion for sqrt(3) - 1, where r(k) = 1/(2k-1).

Original entry on oeis.org

2, 2, 4, 10, 102, 9988, 462079550, 1246459580018549814, 3451767175159069042246539740614797183, 16047263805335625632784779620610026996218698731392917143951229224582015756

Offset: 1

Clark Kimberling, Apr 02 2016

Suppose that r is a sequence of rational numbers r(k) <= 1 for k >= 1, and that x is an irrational number in (0,1). Let f(0) = x, n(k) = floor(r(k)/f(k-1)), and f(k) = f(k-1) - r(k)/n(k). Then x = r(1)/n(1) + r(2)/n(2) + r(3)/n(3) + ..., the r-Egyptian fraction for x.

See A269993 for a guide to related sequences.

			sqrt(3) - 1 = 1/(1*2) + 1/(3*2) + 1/(5*4) + 1/(7*10) + ...

Clark Kimberling, Table of n, a(n) for n = 1..13
Eric Weisstein's World of Mathematics, Egyptian Fraction
Index entries for sequences related to Egyptian fractions

Cf. A269993, A005408, A160390.

r[k_] := 1/(2k-1); f[x_, 0] = x; z = 10;
n[x_, k_] := n[x, k] = Ceiling[r[k]/f[x, k - 1]]
f[x_, k_] := f[x, k] = f[x, k - 1] - r[k]/n[x, k]
x = Sqrt(3) - 1; Table[n[x, k], {k, 1, z}]

r(k) = 1/(2*k-1);
f(k,x) = if (k==0, x, f(k-1, x) - r(k)/a(k, x););
a(k, x=sqrt(3)-1) = ceil(r(k)/f(k-1, x)); \\ Michel Marcus, Apr 03 2016

A302708 Constant of a logarithmic spiral interpolating the centers of regular hexagons: (-6/Pi)*log(-1 + sqrt(3)).

Original entry on oeis.org

5, 9, 5, 6, 9, 5, 3, 5, 4, 3, 7, 8, 9, 9, 3, 4, 1, 9, 8, 7, 8, 9, 6, 6, 1, 3, 3, 7, 7, 5, 3, 6, 0, 1, 7, 3, 7, 1, 2, 3, 1, 3, 1, 5, 4, 5, 8, 2, 8, 8, 7, 2, 6, 6, 8, 6, 6, 7, 6, 6, 0, 7, 5, 0, 3, 2, 9, 2, 5, 3, 3, 4, 8, 7, 0, 8, 3, 0, 2, 9, 0, 5, 7, 8, 5, 2, 4, 7, 9, 8, 3, 7, 4, 7, 9, 2, 4, 0, 8, 6, 5, 9, 5

Offset: 0

Wolfdieter Lang, Apr 14 2018

For the sequence of regular hexagons H_k with centers 0_k, for integers k, see the link. These centers form a discrete spiral which is interpolated by a logarithmic spiral r(phi) = exp(-kappa*phi) with origin S = (0, 1) if the hexagon H_0 has center 0_0 = (0, 0), inscribed in a circle of radius 1 length unit, and a vertex V_0(0) = (1, 0). In the link this coordinate system is called (x_0, y_0). The constant of the logarithmic spiral is kappa = (-6/Pi)*log(-1 + sqrt(3)). For -1 + sqrt(3) (the scaling factor for the hexagons called sigma in the linked paper) see A160390.

The constant angle between the radial direction of a spiral point and the tangent is given by arccot(kappa) approximately 1.033548019, corresponding to an angle of about 59.218 degrees (complementary to 120.782 degrees).

			0.59569535437899341987896613377536017371231315458288726686676607503292533487083...

Wolfdieter Lang, On a Conformal Mapping of Regular Hexagons and the Spiral of its Centers.

Cf. A160390.

RealDigits[6*Log[Sqrt[3] - 1]/Pi, 10, 120][[1]] (* Amiram Eldar, Jun 12 2023 *)

default(realprecision,120); -(6/Pi)*log(-1 + sqrt(3)) \\ Georg Fischer, Jul 18 2021

Equals -(6/Pi)*log(-1 + sqrt(3)) = -(6/Pi)*log(A160390).

a(102) corrected by Georg Fischer, Jul 18 2021

A344111 Decimal expansion of 4 + sqrt(3).

Original entry on oeis.org

5, 7, 3, 2, 0, 5, 0, 8, 0, 7, 5, 6, 8, 8, 7, 7, 2, 9, 3, 5, 2, 7, 4, 4, 6, 3, 4, 1, 5, 0, 5, 8, 7, 2, 3, 6, 6, 9, 4, 2, 8, 0, 5, 2, 5, 3, 8, 1, 0, 3, 8, 0, 6, 2, 8, 0, 5, 5, 8, 0, 6, 9, 7, 9, 4, 5, 1, 9, 3, 3, 0, 1, 6, 9, 0, 8, 8, 0, 0, 0, 3, 7, 0, 8, 1, 1, 4, 6, 1, 8, 6, 7, 5

Offset: 1

Wesley Ivan Hurt, May 10 2021

Decimal expansion of the surface area of a gyrobifastigium with regular faces and unit edge length.

Essentially the same sequence of digits as A176102, A165663, A160390, A090388, A019973 and A002194. - R. J. Mathar, May 16 2021

			5.73205080756887729...

Wikipedia, Gyrobifastigium

Cf. A002194, A019973, A090388, A160390, A165663.

RealDigits[4 + Sqrt[3], 10, 100] // Flatten

cp's OEIS Frontend

A134451 Ternary digital root of n.

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A048788 a(2n+1) = a(2n) + a(2n-1), a(2n) = 2*a(2n-1) + a(2n-2); a(n) = n for n = 0, 1.

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A165663 Decimal expansion of 3 + sqrt(3).

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A286389 a(0) = 0; a(n) = n - a(floor(a(n-1)/2)).

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A138466 a(1)=1; for n >= 2, a(n) = n - floor((1/2)*a(a(n-1))).

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A270397 Denominators of r-Egyptian fraction expansion for sqrt(3) - 1, where r(k) = 1/Fibonacci(k+1).

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