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 1-9 of 9 results.

A091401 Numbers n such that genus of group Gamma_0(n) is zero.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 16, 18, 25
Offset: 1

Views

Author

N. J. A. Sloane, Mar 02 2004

Keywords

Comments

Equivalently, numbers n such that genus of modular curve X_0(n) is zero.

References

  • G. Shimura, Introduction to the Arithmetic Theory of Automorphic Functions, Princeton, 1971, see Prop. 1.40 and 1.43.

Crossrefs

The table below is a consequence of Theorem 7.3 in Maier's paper.
N EntryID K alpha
1
2 A127776 4096 1
3 A276018 729 1
4 A002894 256 1
5 A276019 125 4
6 A093388 72 1
7 A276021 49 9
8 A081085 32 1
9 A006077 27 1
10 A276020 20 2
12 A276022 12 1
13 A276177 13 36
16 A276178 8 1
18 A276179 6 1
25 A276180 5 4

Programs

Formula

Numbers n such that A001617(n) = 0.

A276019 n^2 * a(n) = (88*n^2 - 132*n + 54) * a(n-1) - 500*(2*n-3)^2 * a(n-2), with a(0)=1, a(1)=10.

Original entry on oeis.org

1, 10, 230, 6500, 199750, 6366060, 204990300, 6539387400, 202432551750, 5897526329500, 151804596385780, 2807347223915000, -15232296765302500, -5584390420089725000, -416025902106681525000, -24002385182809425846000, -1235898175219724085176250, -59486502796252242452122500, -2731496764897242177292037500, -120874274801920384164027025000, -5181210157044172846922944311500
Offset: 0

Views

Author

Gheorghe Coserea, Aug 23 2016

Keywords

Examples

			A(x) = 1 + 10*x + 230*x^2 + 6500*x^3 + ... is the g.f.
		

Crossrefs

Programs

  • PARI
    seq(N) = {
      a = vector(N); a[1] = 10; a[2] = 230;
      for (n = 3, N, a[n] = ((88*n^2 - 132*n + 54)*a[n-1] - 500*(2*n-3)^2 * a[n-2])/n^2);
      concat(1, a);
    };
    seq(20)

Formula

n^2*a(n) = (88*n^2-132*n+54)*a(n-1) - 500*(2*n-3)^2*a(n-2), with a(0)=1, a(1)=10.
0 = 4*x*(x^2+22*x+125)*y'' + (8*x^2+132*x+500)*y' + (x+10)*y, where y(x) = A(x/-500).

A276020 n^2 * a(n) = 2*(17*n^2-21*n+9) * a(n-1) - 4*(112*n^2-280*n+197) * a(n-2) + 40*(68*n^2-256*n+251) * a(n-3) - 1600*(2*n-5)^2 * a(n-4), with a(0)=1, a(1)=10, a(2)=90, a(3)=780.

Original entry on oeis.org

1, 10, 90, 780, 6630, 55820, 469220, 3967000, 33951750, 295553500, 2622492940, 23701797800, 217528135900, 2018704327800, 18862262001800, 176834576018480, 1659586559786950, 15575074941839100, 146164364053448700, 1372547571923176200, 12910383388613518580, 121770360957324308200, 1152648798132152849400
Offset: 0

Views

Author

Gheorghe Coserea, Aug 23 2016

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 10; a[2] = 90; a[3] = 780; a[n_] := a[n] = (40(68n^2 - 256n + 251)a[n-3] - 4(112n^2 - 280n + 197)a[n-2] + 2(17n^2 - 21n + 9)a[n-1] - 1600(2n - 5)^2 a[n-4])/n^2;
    Table[a[n], {n, 0, 22}] (* Jean-François Alcover, Oct 19 2018 *)
  • PARI
    seq(N) = {
      my(a = vector(N));
      a[1] = 10; a[2] = 90; a[3] = 780; a[4] = 6630;
      for (n = 5, N,
        my(t1 = 2*(17*n^2 - 21*n + 9)*a[n-1] - 4*(112*n^2 - 280*n + 197)*a[n-2],
           t2 = 40*(68*n^2 - 256*n + 251) * a[n-3] - 1600*(2*n-5)^2 *a[n-4]);
        a[n] = (t1 + t2)/n^2);
      concat(1,a);
    };
    seq(22)

Formula

n^2*a(n) = 2*(17*n^2-21*n+9)*a(n-1) - 4*(112*n^2-280*n+197)*a(n-2) + 40*(68*n^2-256*n+251)*a(n-3) - 1600*(2*n-5)^2 *a(n-4), with a(0)=1, a(1)=10, a(2)=90, a(3)=780.
0 = 4*x*(x+4)*(x+5)*(x^2+8*x+20)*y'' + 4*(4*x^4+55*x^3+280*x^2+600*x+400)*y' + (9*x^3+95*x^2+340*x+400)*y, where y(x) = A(x/-40).
a(n) ~ 2^n * 5^(n+5/4) / (Pi*n). - Vaclav Kotesovec, Aug 25 2016

A276021 n^2 * a(n) = 3*(39*n^2 - 52*n + 20) * a(n-1) - 441*(3*n-4)^2 * a(n-2), with a(0)=1, a(1)=21.

Original entry on oeis.org

1, 21, 693, 23940, 734643, 13697019, -494620749, -83079255420, -6814815765975, -444980496382695, -25071954462140859, -1226361084729855984, -49426887403935395172, -1287188243957889124740, 23935850133162849385308, 6798920856226697943604944, 650950202721260061404073891
Offset: 0

Views

Author

Gheorghe Coserea, Aug 23 2016

Keywords

Examples

			A(x) = 1 + 21*x + 693*x^2 + 23940*x^3 + ... is the g.f.
		

Crossrefs

Programs

  • Magma
    I:=[21,693]; [1] cat [n le 2 select I[n] else (3*(39*n^2-52*n+20)*Self(n-1)-441*(3*n-4)^2*Self(n-2)) div n^2: n in [1..30]]; // Vincenzo Librandi, Aug 25 2016
  • Mathematica
    a[0] = 1; a[1] = 21; a[n_] := a[n] = (3(39n^2 - 52n + 20) a[n-1] - 441(3n - 4)^2 a[n-2])/n^2;
    Table[a[n], {n, 0, 16}] (* Jean-François Alcover, Oct 19 2018 *)
  • PARI
    seq(N) = {
      my(a = vector(N)); a[1] = 21; a[2] = 693;
      for (n=3, N,
           a[n] = (3*(39*n^2 - 52*n + 20) * a[n-1] - 441*(3*n-4)^2 * a[n-2])/n^2);
      concat(1,a);
    };
    seq(17)
    

Formula

n^2 * a(n) = 3*(39*n^2-52*n+20) * a(n-1) - 441*(3*n-4)^2 * a(n-2), with a(0)=1, a(1)=21.
0 = 9*x*(x^2+13*x+49)*y'' + (21*x^2 + 195*x + 441)*y' + (4*x+21)*y, where y(x) = A(x/-441).

A276022 n^2 * a(n) = 3*(5*n^2 - 5*n + 2) * a(n-1) - 16*(5*n^2 - 10*n + 6) * a(n-2) + 36*(5*n^2 - 15*n + 12) * a(n-3) - 144*(n-2)^2 * a(n-4), with a(0)=1, a(1)=6, a(2)=30, a(3)=144.

Original entry on oeis.org

1, 6, 30, 144, 690, 3348, 16536, 83232, 426618, 2223180, 11756052, 62959680, 340881792, 1862954784, 10262937600, 56926831104, 317632207194, 1781352834300, 10034760283356, 56748881420640, 322033934657628, 1833043230774360, 10462349697348528, 59861990921495616
Offset: 0

Views

Author

Gheorghe Coserea, Aug 23 2016

Keywords

Examples

			A(x) = 1 + 6*x + 30*x^2 + 144*x^3 + ... is the g.f.
		

Crossrefs

Programs

  • Magma
    I:=[6,30,144,690]; [1] cat [n le 4 select I[n] else (3*(5*n^2-5*n+2)*Self(n-1)-16*(5*n^2-10*n+6)*Self(n-2)+36*(5*n^2-15*n+12)*Self(n-3)-144*(n-2)^2*Self(n-4)) div n^2: n in [1..30]]; // Vincenzo Librandi, Aug 25 2016
  • Mathematica
    a[0] = 1; a[1] = 6; a[2] = 30; a[3] = 144; a[n_] := a[n] = (3(5n^2 - 5n + 2) a[n-1] - 16(5n^2 - 10n + 6)a[n-2] + 36(5n^2 - 15n + 12) a[n-3] - 144(n-2)^2 a[n-4])/n^2;
    Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Oct 19 2018 *)
  • PARI
    seq(N) = {
      my(a = vector(N)); a[1] = 6; a[2] = 30; a[3] = 144; a[4] = 690;
      for (n=5, N,
           my(t1 = 3*(5*n^2 - 5*n + 2)*a[n-1] - 16*(5*n^2 - 10*n + 6)*a[n-2],
              t2 = 36*(5*n^2 - 15*n + 12)*a[n-3] - 144*(n-2)^2 * a[n-4]);
           a[n] = (t1+t2)/n^2);
      concat(1,a);
    };
    seq(25)
    

Formula

n^2 * a(n) = 3*(5*n^2 - 5*n + 2) * a(n-1) - 16*(5*n^2 - 10*n + 6) * a(n-2) + 36*(5*n^2 - 15*n + 12) * a(n-3) - 144*(n-2)^2 * a(n-4), with a(0)=1, a(1)=6, a(2)=30, a(3)=144.
0 = x*(x+2)*(x+3)*(x+4)*(x+6)*y'' + (5*x^4 + 60*x^3 + 240*x^2 + 360*x + 144)*y' + 4*(x^2+6*x+6)*(x+3)*y, where y(x) = A(x/-12).
a(n) ~ 2^n * 3^(n+3/2) / (Pi*n). - Vaclav Kotesovec, Aug 25 2016

A276177 n^2 * a(n) = 6*(66*n^2 - 94*n + 41) * a(n-1) - 36*(2016*n^2 - 5712*n + 4387) * a(n-2) + 50544*(132*n^2 - 560*n + 609) * a(n-3) - 7884864*(6*n-17)^2*a(n-4), with a(0)=1, a(1)=78, a(2)=4446, a(3)=20124.

Original entry on oeis.org

1, 78, 4446, 20124, -38185290, -6138851004, -560711991060, -21068540562888, 3057536757534246, 744702083933794740, 85203074089262120004, 5052846560269468159368, -180318018879496001303748, -86176724948835065345458008, -11276003918572185562671306600, -751248675388448553292016521104
Offset: 0

Views

Author

Gheorghe Coserea, Aug 23 2016

Keywords

Examples

			A(x) = 1 + 78*x + 4446*x^2 + 20124*x^3 + ... is the g.f.
		

Crossrefs

Programs

  • Magma
    I:=[78,4446,20124,-38185290]; [1] cat [n le 4 select I[n] else (6*(66*n^2-94*n+41)*Self(n-1)-36*(2016*n^2-5712*n+4387)*Self(n-2)+50544*(132*n^2-560*n+ 609)*Self(n-3)-7884864*(6*n-17)^2*Self(n-4)) div n^2: n in [1..30]]; // Vincenzo Librandi, Aug 25 2016
  • Mathematica
    a[0] = 1; a[1] = 78; a[2] = 4446; a[3] = 20124; a[n_] := a[n] = (6(66n^2 - 94n + 41) a[n-1] - 36(2016n^2 - 5712n + 4387)a[n-2] + 50544(132n^2 - 560n + 609)a[n-3] - 7884864(6n - 17)^2 a[n-4])/n^2;
    Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Oct 19 2018 *)
  • PARI
    seq(N) = {
      my(a = vector(N));
      a[1] = 78; a[2] = 4446; a[3] = 20124; a[4] = -38185290;
      for (n = 5, N,
           my(t1 = 6*(66*n^2 - 94*n + 41) * a[n-1],
              t2 = -36*(2016*n^2 - 5712*n + 4387) * a[n-2],
              t3 = 50544*(132*n^2 - 560*n + 609) * a[n-3],
              t4 = -7884864*(6*n-17)^2 * a[n-4]);
           a[n] = (t1 + t2 + t3 + t4)/n^2);
      concat(1,a);
    };
    seq(17)
    

Formula

n^2 * a(n) = 6*(66*n^2 - 94*n + 41) * a(n-1) - 36*(2016*n^2 - 5712*n + 4387) * a(n-2) + 50544*(132*n^2 - 560*n + 609) * a(n-3) - 7884864*(6*n-17)^2*a(n-4), with a(0)=1, a(1)=78, a(2)=4446, a(3)=20124.
0 = 36*x*(x^2 + 5*x + 13)*(x^2 + 6*x + 13)*y'' + 12*(10*x^4 + 91*x^3 + 364*x^2 + 676*x + 507)*y' + (49*x^3 + 351*x^2 + 1027*x + 1014)*y, where y(x) = A(x/-468).

A276178 G.f.: 1/AGM(1, (1-4*x)^2).

Original entry on oeis.org

1, 4, 12, 32, 84, 240, 784, 2816, 10404, 38096, 137456, 493440, 1783376, 6532288, 24245568, 90814464, 341776164, 1289126160, 4870386736, 18439692928, 70004793936, 266551445952, 1017708956224, 3894679004160, 14932998810896, 57349426579264, 220574904103872, 849571289810432
Offset: 0

Views

Author

Gheorghe Coserea, Aug 23 2016

Keywords

Examples

			A(x) = 1 + 4*x + 12*x^2 + 32*x^3 + ... is the g.f.
		

Crossrefs

Programs

  • Mathematica
    a[n_] = DifferenceRoot[Function[{a, n}, {(-80 n^2 - 400n - 512) a[n+1] + (40n^2 + 240n + 368) a[n+2] + (-10n^2 - 70n - 124) a[n+3] + 64(n+2)^2 a[n] + (n+4)^2 a[n+4] == 0, a[0] == 1, a[1] == 4, a[2] == 12, a[3] == 32}]][n];
    Table[a[n], {n, 0, 27}]
    (* or: *)
    Series[1/FunctionExpand[ArithmeticGeometricMean[1, (1-4x)^2], 1-4x > 0], {x, 0, 28}] // CoefficientList[#, x]& (* Jean-François Alcover, Dec 18 2018 *)
  • PARI
    N=34; x='x + O('x^N); Vec(1/agm(1, (1-4*x)^2))

Formula

G.f.: 1/agm(1, (1-4*x)^2).
0 = x*(x+2)*(x+4)*(x^2 + 4*x + 8) * y'' + (5*x^4 + 40*x^3 + 120*x^2 + 160*x + 64) * y' + 4*(x+2)^3 * y, where y(x) = A(x/-8).
From Vaclav Kotesovec, Aug 25 2016: (Start)
Recurrence: n^2*a(n) = 2*(5*n^2 - 5*n + 2)*a(n-1) - 8*(5*n^2 - 10*n + 6)*a(n-2) + 16*(5*n^2 - 15*n + 12)*a(n-3) - 64*(n-2)^2*a(n-4).
a(n) ~ 2^(2*n+2)/(Pi*n).
(End)

A276179 n^2 * a(n) = 2*(7*n^2 - 7*n + 3)*a(n-1) - 12*(7*n^2 - 14*n + 9)*a(n-2) + 39*(7*n^2 - 21*n + 18) * a(n-3) - 72*(7*n^2 - 28*n + 30)*a(n-4) + 72*(7*n^2 - 35*n + 45) * a(n-5) - 216*(n-3)^2 * a(n-6), with a(0)=1, a(1)=6, a(2)=24, a(3)=78, a(4)=216, a(5)=504.

Original entry on oeis.org

1, 6, 24, 78, 216, 504, 906, 756, -2808, -17832, -57312, -104832, 81882, 1734156, 9360576, 35755956, 106475472, 232967664, 215497680, -1178534304, -8734303296, -36146763648, -108833048064, -220247838720, -46688571558, 2220777704700, 13473296923536, 53523581091900
Offset: 0

Views

Author

Gheorghe Coserea, Aug 24 2016

Keywords

Examples

			A(x) = 1 + 6*x + 24*x^2 + 78*x^3 + 216*x^4 + 504*x^5 + 906*x^6 + ... is the g.f.
		

Crossrefs

Programs

  • Magma
    I:=[6,24,78,216,504,906]; [1] cat [n le 6 select I[n] else (2*(7*n^2-7*n+3)*Self(n-1)-12*(7*n^2-14*n+9)*Self(n-2)+39*(7*n^2-21*n+18)*Self(n-3)-72*(7*n^2-28*n+30)*Self(n-4)+72*(7*n^2-35*n+45)*Self(n-5)-216*(n-3)^2*Self(n-6)) div n^2: n in [1..30]]; // Vincenzo Librandi, Aug 25 2016
  • PARI
    seq(N) = {
      my(a = vector(N));
      a[1] = 6; a[2] = 24; a[3] = 78; a[4] = 216; a[5] = 504; a[6] = 906;
      for (n = 7, N,
      my(t1 = 2*(7*n^2 - 7*n + 3)*a[n-1] - 12*(7*n^2 - 14*n + 9)*a[n-2],
         t2 = 39*(7*n^2 - 21*n + 18) * a[n-3] - 72*(7*n^2 - 28*n + 30)*a[n-4],
         t3 = 72*(7*n^2 - 35*n + 45) * a[n-5] - 216*(n-3)^2 * a[n-6]);
         a[n] = (t1+t2+t3)/n^2);
      concat(1,a);
    };
    seq(33)
    

Formula

n^2 * a(n) = 2*(7*n^2 - 7*n + 3)*a(n-1) - 12*(7*n^2 - 14*n + 9)*a(n-2) + 39*(7*n^2 - 21*n + 18) * a(n-3) - 72*(7*n^2 - 28*n + 30)*a(n-4) + 72*(7*n^2 - 35*n + 45) * a(n-5) - 216*(n-3)^2 * a(n-6), with a(0)=1, a(1)=6, a(2)=24, a(3)=78, a(4)=216, a(5)=504.
0 = x*(x+2)*(x+3)*(x^2+3*x+3)*(x^2+6*x+12)*y'' + (7*x^6 + 84*x^5 + 420*x^4 + 1092*x^3 + 1512*x^2 + 1008*x + 216)*y' + 9*(x+2)^2 * (x^3 + 6*x^2 + 12*x + 6)*y, where y(x) = A(x/-6).

A276180 n^2*a(n) = 2*(14*n^2 - 16*n + 7)*a(n-1) - 20*(24*n^2 - 56*n + 41)*a(n-2) + 80*(64*n^2 - 224*n + 221)*a(n-3) - 1600*(24*n^2 - 112*n + 139)*a(n-4) + 6400*(28*n^2 - 164*n + 245)*a(n-5) - 128000*(2*n-7)^2*a(n-6) for n>6, a(0)=1, a(1)=10, a(2)=30, a(3)=-300, a(4)=-3850, a(5)=-13940, a(6) = 56300.

Original entry on oeis.org

1, 10, 30, -300, -3850, -13940, 56300, 543400, -2332250, -29758500, 340835780, 7316239000, 40381709500, -199606565000, -4494519345000, -25429880846000, 18331676223750, 848074482677500, 714616060812500, -19019302889325000, 506727569992188500
Offset: 0

Views

Author

Gheorghe Coserea, Aug 24 2016

Keywords

Examples

			A(x) = 1 + 10*x + 30*x^2 - 300*x^3 - 3850*x^4 - 13940*x^5 + ... is the g.f.
		

Crossrefs

Programs

  • Magma
    I:=[10,30,-300,-3850,-13940,56300]; [1] cat [n le 6 select I[n] else (2*(14*n^2-16*n+7)*Self(n-1)-20*(24*n^2- 56*n+41)*Self(n-2)+80*(64*n^2-224*n+221)*Self(n-3)-1600*(24*n^2-112*n+139)*Self(n-4)+6400*(28*n^2-164*n+245)*Self(n-5)-128000*(2*n-7)^2*Self(n-6))div n^2: n in [1..30]]; // Vincenzo Librandi, Aug 25 2016
  • Mathematica
    a[n_] := a[n] = If[n <= 6, {1, 10, 30, -300, -3850, -13940, 56300}[[n+1]], (1/n^2)(6400(28n^2 - 164n + 245) a[n-5] - 1600(24n^2 - 112n + 139) a[n-4] + 80(64n^2 - 224n + 221) a[n-3] - 20(24n^2 - 56n + 41) a[n-2] + 2(14n^2 - 16n + 7) a[n-1] - 128000(2n - 7)^2 a[n-6])];
    Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Dec 16 2018 *)
  • PARI
    seq(N) = {
      my(a = vector(N));
      a[1] = 10; a[2] = 30; a[3] = -300; a[4] = -3850; a[5] = -13940; a[6] = 56300;
      for (n=7, N,
      my(t1 = 2*(14*n^2 - 16*n + 7)*a[n-1] - 20*(24*n^2 - 56*n + 41)*a[n-2],
         t2 = 80*(64*n^2 - 224*n + 221)*a[n-3] - 1600*(24*n^2 - 112*n + 139)*a[n-4],
         t3 = 6400*(28*n^2 - 164*n + 245)*a[n-5] - 128000*(2*n-7)^2 * a[n-6]);
      a[n] = (t1+t2+t3)/n^2);
      concat(1,a);
    };
    seq(25)
    

Formula

n^2*a(n) = 2*(14*n^2 - 16*n + 7)*a(n-1) - 20*(24*n^2 - 56*n + 41)*a(n-2) + 80*(64*n^2 - 224*n + 221)*a(n-3) - 1600*(24*n^2 - 112*n + 139)*a(n-4) + 6400*(28*n^2 - 164*n + 245)*a(n-5) - 128000*(2*n-7)^2*a(n-6) for n>6, a(0)=1, a(1)=10, a(2)=30, a(3)=-300, a(4)=-3850, a(5)=-13940, a(6)=56300.
0 = 4*x*(x^2+2*x+5)*(x^4+5*x^3+15*x^2+25*x+25)*y'' + (24*x^6 + 144*x^5 + 520*x^4 + 1120*x^3 + 1600*x^2 + 1300*x + 500)*y' + 25*(x^5 + 5*x^4 + 15*x^3 + 25*x^2 + 25*x + 10)*y, where y(x) = A(x/-20).
Showing 1-9 of 9 results.