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.

Showing 1-3 of 3 results.

A130610 Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+359)^2 = y^2.

Original entry on oeis.org

0, 40, 901, 1077, 1281, 6160, 7180, 8364, 36777, 42721, 49621, 215220, 249864, 290080, 1255261, 1457181, 1691577, 7317064, 8493940, 9860100, 42647841, 49507177, 57469741, 248570700, 288549840, 334959064, 1448777077, 1681792581
Offset: 1

Views

Author

Mohamed Bouhamida, Jun 17 2007

Keywords

Comments

Also values x of Pythagorean triples (x, x+359, y).
Corresponding values y of solutions (x, y) are in A159844.
For the generic case x^2+(x+p)^2 = y^2 with p = m^2-2 a (prime) number > 7 in A028871, see A118337.
lim_{n -> infinity} a(n)/a(n-3) = 3+2*sqrt(2).
lim_{n -> infinity} a(n)/a(n-1) = (363+38*sqrt(2))/359 for n mod 3 = {1, 2}.
lim_{n -> infinity} a(n)/a(n-1) = (293619+186550*sqrt(2))/359^2 for n mod 3 = 0.

Links

Crossrefs

Cf. A159844, A028871, A118337, A130609, A001652, A156035 (decimal expansion of 3+2*sqrt(2)), A159845 (decimal expansion of (363+38*sqrt(2))/359), A159846 (decimal expansion of (293619+186550*sqrt(2))/359^2).

Programs

  • PARI
    {forstep(n=0, 100000000, [1, 3], if(issquare(2*n^2+718*n+128881), print1(n, ",")))}

Formula

a(n) = 6*a(n-3)-a(n-6)+718 for n > 6; a(1)=0, a(2)=40, a(3)=901, a(4)=1077, a(5)=1281, a(6)=6160.
G.f.: x*(40+861*x+176*x^2-36*x^3-287*x^4-36*x^5) / ((1-x)*(1-6*x^3+x^6)).
a(3*k+1) = 359*A001652(k) for k >= 0.

Extensions

Edited and two terms added by Klaus Brockhaus, Apr 30 2009

A159844 Positive numbers y such that y^2 is of the form x^2+(x+359)^2 with integer x.

Original entry on oeis.org

325, 359, 401, 1549, 1795, 2081, 8969, 10411, 12085, 52265, 60671, 70429, 304621, 353615, 410489, 1775461, 2061019, 2392505, 10348145, 12012499, 13944541, 60313409, 70013975, 81274741, 351532309, 408071351, 473703905, 2048880445
Offset: 1

Views

Author

Klaus Brockhaus, Apr 30 2009

Keywords

Comments

(-36, a(1)) and (A130610(n), a(n+1)) are solutions (x, y) to the Diophantine equation x^2+(x+359)^2 = y^2.
lim_{n -> infinity} a(n)/a(n-3) = 3+2*sqrt(2).
lim_{n -> infinity} a(n)/a(n-1) = (363+38*sqrt(2))/359 for n mod 3 = {0, 2}.
lim_{n -> infinity} a(n)/a(n-1) = (293619+186550*sqrt(2))/359^2 for n mod 3 = 1.
For the generic case x^2+(x+p)^2=y^2 with p=m^2-2 a prime number in A028871, m>=5, the x values are given by the sequence defined by: a(n)=6*a(n-3)-a(n-6)+2p with a(1)=0, a(2)=2m+2, a(3)=3m^2-10m+8, a(4)=3p, a(5)=3m^2+10m+8, a(6)=20m^2-58m+42.Y values are given by the sequence defined by: b(n)=6*b(n-3)-b(n-6) with b(1)=p, b(2)=m^2+2m+2, b(3)=5m^2-14m+10, b(4)=5p, b(5)=5m^2+14m+10, b(6)=29m^2-82m+58. [Mohamed Bouhamida, Sep 09 2009]

Examples

			(-36, a(1)) = (-36, 325) is a solution: (-36)^2+(-36+359)^2 = 1296+104329 = 105625 = 325^2.
(A130610(1), a(2)) = (0, 359) is a solution: 0^2+(0+359)^2 = 128881 = 359^2.
(A130610(3), a(4)) = (901, 1549) is a solution: 901^2+(901+359)^2 = 811801+1587600 = 2399401 = 1549^2.

Links

Crossrefs

Cf. A130610, A001653, A156035 (decimal expansion of 3+2*sqrt(2)), A159845 (decimal expansion of (363+38*sqrt(2))/359), A159846 (decimal expansion of (293619+186550*sqrt(2))/359^2).

Programs

  • Magma
    I:=[325, 359, 401, 1549, 1795, 2081]; [n le 6 select I[n] else 6*Self(n-3) - Self(n-6): n in [1..30]]; // G. C. Greubel, May 19 2018
  • Mathematica
    t={325,359,401,1549,1795,2081}; Do[AppendTo[t, 6*t[[-3]]-t[[-6]]], {25}]; t
CoefficientList[Series[(325+359 x+401 x^2-401 x^3-359 x^4-325 x^5)/(1-6 x^3+x^6),{x,0,30}],x]  (* Harvey P. Dale, Feb 16 2011 *)
LinearRecurrence[{0,0,6,0,0,-1}, {325, 359, 401, 1549, 1795, 2081}, 50] (* G. C. Greubel, May 19 2018 *)
  • PARI
    {forstep(n=-36, 10000000, [1, 3], if(issquare(2*n^2+718*n+128881, &k), print1(k, ",")))}
  • PARI
    V=[]; v=[[-323,-325], [-323,325], [0,-359], [-359,359], [-399,-401], [399,401]]; for(n=1,100,u=[]; for(i=1,#v,if(v[i][2]>0, u=concat(u,v[i][2])); t=3*v[i][1]+2*v[i][2]+359; v[i][2]=4*v[i][1]+3*v[i][2]+718; v[i][1]=t); V=concat(V,u)); vecsort(V,,8) \\ Charles R Greathouse IV, Feb 14 2011

Formula

a(n) = 6*a(n-3)-a(n-6) for n > 6; a(1)=325, a(2)=359, a(3)=401, a(4)=1549, a(5)=1795, a(6)=2081.
G.f.: (1-x)*(325+684*x+1085*x^2+684*x^3+325*x^4) / (1-6*x^3+x^6).
a(3*k-1) = 359*A001653(k) for k >= 1.

A159846 Decimal expansion of (293619 + 186550*sqrt(2))/359^2.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 30 2009

Keywords

Comments

Equals lim_{n -> infinity} b(n)/b(n-1) for n mod 3 = 0, b = A130610.
Equals lim_{n -> infinity} b(n)/b(n-1) for n mod 3 = 1, b = A159844.

Examples

			(293619 + 186550*sqrt(2))/359^2 = 4.32523444154453240860...

Links

Crossrefs

Cf. A130610, A159844, A002193 (decimal expansion of sqrt(2)), A159845 (decimal expansion of (363+38*sqrt(2))/359).

Programs

  • Magma
    (293619 +186550*Sqrt(2))/359^2; // G. C. Greubel, May 19 2018
  • Mathematica
    RealDigits[(293619+186550Sqrt[2])/359^2,10,120][[1]] (* Harvey P. Dale, Jun 14 2011 *)
  • PARI
    (293619 +186550*sqrt(2))/359^2 \\ G. C Greubel, May 19 2018

Formula

Equals (650 + 287*sqrt(2))/(650 - 287*sqrt(2)).
Equals (3 + 2*sqrt(2))*(19 - sqrt(2))^2/(19 + sqrt(2))^2.
Showing 1-3 of 3 results.

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