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.

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A269550 Expansion of (-5*x^2 + 228*x - 7)/(x^3 - 99*x^2 + 99*x - 1).

Original entry on oeis.org

7, 465, 45347, 4443325, 435400287, 42664784585, 4180713488827, 409667257120245, 40143210484294967, 3933624960203786305, 385455102889486762707, 37770666458209498958765, 3701139857801641411196047, 362673935398102648798253625, 35538344529156257940817658987
Offset: 0

Views

Author

Michel Marcus, Feb 29 2016

Keywords

Comments

Mc Laughlin (2010) gives an identity relating ten sequences, denoted a_k, b_k, ..., f_k, p_k, q_k, r_k, s_k. This is the sequence d_k.

Crossrefs

Programs

  • Magma
    I:=[7,465,45347]; [n le 3 select I[n]  else 99*Self(n-1)+-99*Self(n-2)+Self(n-3): n in [1..20]]; // Vincenzo Librandi, Feb 29 2016
  • Mathematica
    LinearRecurrence[{99, -99, 1}, {7, 465, 45347}, 20] (* Vincenzo Librandi, Feb 29 2016 *)
  • PARI
    Vec((-5*x^2 + 228*x - 7)/(x^3 - 99*x^2 + 99*x - 1) + O(x^20))
    

A269552 Expansion of (-3*x^2 + 94*x - 3)/(x^3 - 99*x^2 + 99*x - 1).

Original entry on oeis.org

3, 203, 19803, 1940403, 190139603, 18631740603, 1825720439403, 178901971320803, 17530567468999203, 1717816709990601003, 168328507011609899003, 16494475870427779501203, 1616290306794910781218803, 158379955590030828779941403, 15519619357516226309653038603, 1520764317081000147517217841603
Offset: 0

Views

Author

Michel Marcus, Feb 29 2016

Keywords

Comments

Mc Laughlin (2010) gives an identity relating ten sequences, denoted a_k, b_k, ..., f_k, p_k, q_k, r_k, s_k. This is the sequence f_k.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(-3x^2+94x-3)/(x^3-99x^2+99x-1),{x,0,20}],x] (* or *) LinearRecurrence[{99,-99,1},{3,203,19803},20] (* Harvey P. Dale, Jan 14 2019 *)
  • PARI
    Vec((-3*x^2 + 94*x - 3)/(x^3 - 99*x^2 + 99*x - 1) + O(x^20))

Formula

G.f.: (-3*x^2 + 94*x - 3)/(x^3 - 99*x^2 + 99*x - 1).
a(n) = 99*a(n-1)-99*a(n-2)+a(n-3). - Wesley Ivan Hurt, May 20 2021

A269553 Expansion of (-5*x^2 + 138*x + 3)/(x^3 - 99*x^2 + 99*x - 1).

Original entry on oeis.org

-3, -435, -42763, -4190475, -410623923, -40236954115, -3942810879483, -386355229235355, -37858869654185443, -3709782870880938195, -363520862476677757803, -35621334739843539326635, -3490527283642190176252563, -342036052462194793733424675, -33516042614011447595699365723
Offset: 0

Views

Author

Michel Marcus, Feb 29 2016

Keywords

Comments

Mc Laughlin (2010) gives an identity relating ten sequences, denoted a_k, b_k, ..., f_k, p_k, q_k, r_k, s_k. This is the sequence p_k.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{99, -99, 1}, {-3, -435, -42763}, 20] (* Paolo Xausa, Mar 04 2024 *)
  • PARI
    Vec((-5*x^2 + 138*x + 3)/(x^3 - 99*x^2 + 99*x - 1) + O(x^20))

A269554 Expansion of (3*x^2 + 244*x + 1)/(x^3 - 99*x^2 + 99*x - 1).

Original entry on oeis.org

-1, -343, -33861, -3318283, -325158121, -31862177823, -3122168268781, -305940628162963, -29979059391701841, -2937641879758617703, -287858925156952833301, -28207237023501619046043, -2764021369378001713679161, -270845886962020666321511983, -26540132900908647297794495421
Offset: 0

Views

Author

Michel Marcus, Feb 29 2016

Keywords

Comments

Mc Laughlin (2010) gives an identity relating ten sequences, denoted a_k, b_k, ..., f_k, p_k, q_k, r_k, s_k. This is the sequence q_k.

Crossrefs

Programs

  • Magma
    m:=20; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((3*x^2+244*x+1)/(x^3-99*x^2+99*x-1))); // Bruno Berselli, Mar 02 2016
  • Mathematica
    CoefficientList[Series[(3 x^2 + 244 x + 1)/(x^3 - 99 x^2 + 99 x - 1), {x, 0, 20}], x] (* or *) Table[Simplify[31/12 + ((17 Sqrt[6] - 43)/(2 Sqrt[6] + 5)^(2 n) - (17 Sqrt[6] + 43) (2 Sqrt[6] + 5)^(2 n))/24], {n, 0, 20}] (* Bruno Berselli, Mar 02 2016 *)
    LinearRecurrence[{99,-99,1},{-1,-343,-33861},20] (* Harvey P. Dale, Feb 03 2025 *)
  • PARI
    Vec((3*x^2 + 244*x + 1)/(x^3 - 99*x^2 + 99*x - 1) + O(x^20))
    
  • Sage
    gf = (3*x^2+244*x+1)/(x^3-99*x^2+99*x-1)
    print(taylor(gf, x, 0, 20).list()) # Bruno Berselli, Mar 02 2016
    

Formula

G.f.: (3*x^2 + 244*x + 1)/(x^3 - 99*x^2 + 99*x - 1).
a(n) = 31/12 + ((17*sqrt(6) - 43)/(2*sqrt(6) + 5)^(2*n) - (17*sqrt(6) + 43)*(2 sqrt(6) + 5)^(2*n))/24. - Bruno Berselli, Mar 02 2016

A269555 Expansion of (x^2 + 254*x - 7)/(x^3 - 99*x^2 + 99*x - 1).

Original entry on oeis.org

7, 439, 42767, 4190479, 410623927, 40236954119, 3942810879487, 386355229235359, 37858869654185447, 3709782870880938199, 363520862476677757807, 35621334739843539326639, 3490527283642190176252567, 342036052462194793733424679, 33516042614011447595699365727, 3284230140120659669584804416319
Offset: 0

Views

Author

Michel Marcus, Feb 29 2016

Keywords

Comments

Mc Laughlin (2010) gives an identity relating ten sequences, denoted a_k, b_k, ..., f_k, p_k, q_k, r_k, s_k. This is the sequence r_k.

Crossrefs

Programs

  • Magma
    m:=20; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((x^2+254*x-7)/(x^3-99*x^2+99*x-1))); // Bruno Berselli, Mar 01 2016
  • Mathematica
    CoefficientList[Series[(x^2 + 254 x - 7)/(x^3 - 99 x^2 + 99 x - 1), {x, 0, 20}], x] (* or *) Table[FullSimplify[31/12 + (-(22 Sqrt[6] - 53)/(2 Sqrt[6] + 5)^(2 n) + (22 Sqrt[6] + 53) (2 Sqrt[6] + 5)^(2 n))/24], {n, 0, 20}] (* Bruno Berselli, Mar 01 2016 *)
    LinearRecurrence[{99,-99,1},{7,439,42767},20] (* Harvey P. Dale, Apr 10 2019 *)
  • PARI
    Vec((x^2 + 254*x - 7)/(x^3 - 99*x^2 + 99*x - 1) + O(x^20))
    
  • Sage
    gf = (x^2+254*x-7)/(x^3-99*x^2+99*x-1)
    print(taylor(gf, x, 0, 20).list()) # Bruno Berselli, Mar 01 2016
    

Formula

G.f.: (x^2 + 254*x - 7)/(x^3 - 99*x^2 + 99*x - 1).
a(n) = 31/12 + (-(22*sqrt(6) - 53)/(2*sqrt(6) + 5)^(2*n) + (22*sqrt(6) + 53)*(2*sqrt(6)+5)^(2*n))/24. - Bruno Berselli, Mar 01 2016

A269556 Expansion of (-7*x^2 + 148*x - 5)/(x^3 - 99*x^2 + 99*x - 1).

Original entry on oeis.org

5, 347, 33865, 3318287, 325158125, 31862177827, 3122168268785, 305940628162967, 29979059391701845, 2937641879758617707, 287858925156952833305, 28207237023501619046047, 2764021369378001713679165, 270845886962020666321511987, 26540132900908647297794495425, 2600662178402085414517539039527
Offset: 0

Views

Author

Michel Marcus, Feb 29 2016

Keywords

Comments

Mc Laughlin (2010) gives an identity relating ten sequences, denoted a_k, b_k, ..., f_k, p_k, q_k, r_k, s_k. This is the sequence s_k.

Crossrefs

Programs

  • Magma
    m:=20; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((-7*x^2+148*x-5)/(x^3-99*x^2+99*x-1))); // Bruno Berselli, Mar 02 2016
  • Mathematica
    CoefficientList[Series[(-7 x^2 + 148 x - 5)/(x^3 - 99 x^2 + 99 x - 1), {x, 0, 20}], x] (* or *) Table[Simplify[17/12 + (-(17 Sqrt[6] - 43)/(2 Sqrt[6] + 5)^(2 n) + (17 Sqrt[6] + 43) (2 Sqrt[6] + 5)^(2 n))/24], {n, 0, 20}] (* Bruno Berselli, Mar 02 2016 *)
  • PARI
    Vec((-7*x^2 + 148*x - 5)/(x^3 - 99*x^2 + 99*x - 1) + O(x^20))
    
  • Sage
    gf = (-7*x^2+148*x-5)/(x^3-99*x^2+99*x-1)
    print(taylor(gf, x, 0, 20).list()) # Bruno Berselli, Mar 02 2016
    

Formula

G.f.: (-7*x^2 + 148*x - 5)/(x^3 - 99*x^2 + 99*x - 1).
a(n) = 17/12 + (-(17*sqrt(6) - 43)/(2*sqrt(6) + 5)^(2*n) + (17*sqrt(6) + 43)*(2 sqrt(6) + 5)^(2*n))/24. - Bruno Berselli, Mar 02 2016

A010703 Period 2: repeat (3,5).

Original entry on oeis.org

3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5
Offset: 0

Views

Author

Keywords

Comments

From Klaus Brockhaus, Dec 10 2009: (Start)
Interleaving of A010701 and A010716.
Also continued fraction expansion of (15+sqrt(285))/10.
Also decimal expansion of 35/99.
Binomial transform of 3 followed by A084633 without initial terms 1,0.
Inverse binomial transform of A171497. (End)

Crossrefs

Cf. A010701 (all 3's sequence), A010716 (all 5's sequence), A084633 (inverse binomial transform of repeated odd numbers), A171497.

Programs

Formula

From Klaus Brockhaus, Dec 10 2009: (Start)
a(n) = a(n-2) for n > 1; a(0) = 3, a(1) = 5.
G.f.: (3+5*x)/((1-x)*(1+x)). (End)
a(n) = 4 - (-1)^n. - Aaron J Grech, Aug 02 2024
E.g.f.: 3*cosh(x) + 5*sinh(x). - Stefano Spezia, Aug 04 2024

A021016 Decimal expansion of 1/12.

Original entry on oeis.org

0, 8, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3
Offset: 0

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Author

Keywords

Comments

Multiplied by -1, this is zeta(-1) or zeta(-13), with zeta being the Riemann zeta function. Divided by 10, this is zeta(-3). - Alonso del Arte, Jan 05 2011
Multiplied by 10, this is 5/6, the resistance in ohm between opposite vertices of a cubical network when each edge has a resistance of 1 ohm. - Michel Marcus, Sep 02 2015
The variance of a continuous uniform distribution U(a,b) is (1/12)*(b-a)^2. - Jean-François Alcover, May 19 2016
5/6 is the Schnirelmann density of the sums of three squares and also the asymptotic density of the set of sums of three squares. See Wagstaff. - Michel Marcus, Apr 22 2020
-1/12 = zeta(-1) is the Ramanujan sum of 1 + 2 + 3 + .... [see facsimile] and was called "one of the most remarkable formulae in science" [Gannon]. - Peter Luschny, Jul 17 2020

Examples

			0.083333333333333333333333333333333333333333333333333333333333333333...
		

References

  • Bruce C. Berndt, Ramanujan's Notebooks: Part 1, Springer-Verlag, 1985, pp. 135-136
  • Terry Gannon, Moonshine Beyond the Monster: The Bridge Connecting Algebra, Modular Forms and Physics, Cambridge University Press, 2010, p. 140.
  • L. B. W. Jolley, Summation of series, Dover Publications Inc. (New York), 1961, p. 40 (series n. 209) and p. 44 (series n. 239).

Crossrefs

Cf. A005408 (odd numbers), A010701.

Programs

Formula

Equals 1/(1*3*5) + 1/(3*5*7) + 1/(5*7*9) + 1/(7*9*11) + ... = Sum_{i >= 0} 1/((2*i+1)*(2*i+3)*(2*i+5)), see Jolley in References. - Bruno Berselli, Mar 21 2014
Equals 1/(2*3*4) + 1/(3*4*5) + 1/(4*5*6) + 1/(5*6*7) + ... = Sum_{i > 0} 1/((i+1)*(i+2)*(i+3)). See Jolley in References, p. 48 (sum obtained from the series 268, case t = 2). - Bruno Berselli, Mar 29 2014
Equals 2*Pi*Integral_{z=-oo..oo} (z/(e^(-Pi*z) + e^(Pi*z)))^2. - Peter Luschny, Jul 17 2020
Equals lim_{x->oo} (P(x) - (1 - t(x))/(1 + t(x)))^(1/x) = lim_{x->oo} (t(x) - (1 - P(x))/(1 + P(x)))^(1/x) by the inversion, where P(x) is the prime zeta function of x and t(x) = zeta(2x)/zeta(x)^2, with zeta(x) being the Riemann zeta function of x. - Thomas Ordowski, Oct 28 2024
Equals Integral_{x>=0} 1/(exp(2*Pi*sqrt(x))-1) dx (Ramanujan, 1913). - Amiram Eldar, Jan 01 2025
Equals Integral_{x=0..1} x^(1/5) - x^(1/3) dx. - Kritsada Moomuang, May 27 2025

A065167 Table T(n,k) read by antidiagonals, where the k-th row gives the permutation t->t+k of Z, folded to N (k >= 0, n >= 1).

Original entry on oeis.org

1, 2, 2, 3, 4, 4, 4, 1, 6, 6, 5, 6, 2, 8, 8, 6, 3, 8, 4, 10, 10, 7, 8, 1, 10, 6, 12, 12, 8, 5, 10, 2, 12, 8, 14, 14, 9, 10, 3, 12, 4, 14, 10, 16, 16, 10, 7, 12, 1, 14, 6, 16, 12, 18, 18, 11, 12, 5, 14, 2, 16, 8, 18, 14, 20, 20, 12, 9, 14, 3, 16, 4, 18, 10, 20, 16, 22, 22, 13, 14, 7, 16, 1
Offset: 0

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Comments

Simple periodic site swap permutations of natural numbers.
Row n of the table (starting from n=0) gives a permutation of natural numbers corresponding to the simple, infinite, periodic site swap pattern ...nnnnn...

Examples

			Table begins:
1 2 3 4 5 6 7 ...
2 4 1 6 3 8 5 ...
4 6 2 8 1 10 3 ...
6 8 4 10 2 12 1 ...
		

Crossrefs

Successive rows and associated site swap sequences, starting from the zeroth row: (A000027, A000004), (A065164, A000012), (A065165, A007395), (A065166, A010701). Cf. also A065171, A065174, A065177. trinv given at A054425.

Programs

  • Maple
    PerSS_table := (n) -> PerSS((((trinv(n)-1)*(((1/2)*trinv(n))+1))-n)+1, (n-((trinv(n)*(trinv(n)-1))/2))); PerSS := (n,c) -> Z2N(N2Z(n)+c);
    N2Z := n -> ((-1)^n)*floor(n/2); Z2N := z -> 2*abs(z)+`if`((z < 1),1,0);
    [seq(PerSS_table(j),j=0..119)];

Formula

Let f: Z -> N be given by f(z) = 2z if z>0 else 2|z|+1, with inverse g(z) = z/2 if z even else (1-z)/2. Then the n-th term of the k-th row is f(g(n)+k).

A078890 Decimal expansion of Sum {n>=0} 1/9^(2^n).

Original entry on oeis.org

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

Views

Author

Robert G. Wilson v, Dec 11 2002

Keywords

Examples

			0.123609229144306327782...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[ N[ Sum[1/9^(2^n), {n, 0, Infinity}], 110]][[1]]
  • PARI
    suminf(n=0, 1/9^(2^n)) \\ Michel Marcus, Nov 11 2020

Formula

Equals A078885 - 1/3 = A078885 - A010701. - R. J. Mathar, Apr 23 2009
Equals -Sum_{k>=1} mu(2*k)/(9^k - 1), where mu is the Möbius function (A008683). - Amiram Eldar, Jul 12 2020
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