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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A037946 Coefficients of unique normalized cusp form Delta_22 of weight 22 for full modular group.

Original entry on oeis.org

1, -288, -128844, -2014208, 21640950, 37107072, -768078808, 1184071680, 6140423133, -6232593600, -94724929188, 259518615552, -80621789794, 221206696704, -2788306561800, 3883087691776, 3052282930002
Offset: 1

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Author

Keywords

Examples

			q^2 - 288*q^4 - ...
		

References

  • G. Harder. "A Congruence Between a Siegel and an Elliptic Modular Form." The 1-2-3 of modular forms. Springer Berlin Heidelberg, 2008. 247-262.

Crossrefs

Cf. A000594 ((E_4(q)^3 - E_6(q)^2)/12^3), A004009 (E_4(q)), A013969, A013973 (E_6(q)), A290181.

Programs

  • Mathematica
    terms = 17;
    E4[x_] = 1 + 240*Sum[k^3*x^k/(1 - x^k), {k, 1, terms+1}];
    E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms+1}];
    ((E4[x]^3 - E6[x]^2)/12^3)*E4[x]*E6[x] + O[x]^(terms+1) // CoefficientList[#, x]& // Rest (* Jean-François Alcover, Feb 27 2018, after Seiichi Manyama *)

Formula

a(n) == A013969(n) mod 77683. - Seiichi Manyama, Feb 03 2017
G.f.: (E_4(q)^3 - E_6(q)^2)/12^3 * E_4(q) * E_6(q). - Seiichi Manyama, Jun 09 2017
G.f.: 691/(1728*250) * (E_8(q)*E_14(q) - E_10(q)*E_12(q)). - Seiichi Manyama, Jul 25 2017

A008689 Theta series of Niemeier lattice of type A_24.

Original entry on oeis.org

1, 600, 182160, 16924320, 397150800, 4632279120, 34414027200, 187479888960, 814930462800, 2975483302200, 9486481747680, 27053266687200, 70486014432960, 169930748683920, 384163827465600
Offset: 0

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Author

Keywords

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

Crossrefs

Programs

  • Mathematica
    terms = 15; E4[q_] := 1 + 240 Sum[DivisorSigma[3, n]*q^(2 n), {n, 1, terms}]; E6[q_] := 1 - 504 Sum[DivisorSigma[5, n]*q^(2 n), {n, 1, terms}]; s = 67/72 E4[q]^3 + 5/72 E6[q]^2 + O[q]^(3 terms); Partition[ CoefficientList[s, q], 2][[All, 1]][[1 ;; terms]] (* Jean-François Alcover, Jul 06 2017 *)

Formula

a(n) = A023936(25n). - Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Aug 02 2001
This series is the q-expansion of 67/72 E_4(z)^3 + 5/72 E_6(z)^2. - Daniel D. Briggs, Nov 25 2011

A008691 Theta series of Niemeier lattice of type A_17 E_7.

Original entry on oeis.org

1, 432, 186192, 16881984, 397398096, 4631467680, 34415043264, 187482701952, 814916270160, 2975502394224, 9486501222240, 27053176872384, 70486076751552, 169930845743904, 384163759953792, 820167146628480, 1668890516764752, 3249628128869472, 6096883839494544
Offset: 0

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Author

Keywords

Comments

Also the theta series for the Niemeier lattice of type D_10 E_7^2. - clarified by Ben Mares, Jul 17 2022

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

Crossrefs

Programs

  • Mathematica
    terms = 15; E4[q_] := 1 + 240 Sum[DivisorSigma[3, n]*q^(2 n), {n, 1, terms}]; E6[q_] := 1 - 504 Sum[DivisorSigma[5, n]*q^(2 n), {n, 1, terms}]; s = 5/6 E4[q]^3 + 1/6 E6[q]^2 + O[q]^(3 terms); Partition[ CoefficientList[s, q], 2][[All, 1]][[1 ;; terms]] (* Jean-François Alcover, Jul 06 2017 *)

Formula

This series is the q-expansion of 5/6 E_4(z)^3 + 1/6 E_6(z)^2. See A004009 and A013973. - Daniel D. Briggs, Nov 25 2011

Extensions

More terms from Sean A. Irvine, Mar 22 2020

A008695 Theta series of Niemeier lattice of type A_11 D_7 E_6.

Original entry on oeis.org

1, 288, 189648, 16845696, 397610064, 4630772160, 34415914176, 187485113088, 814904105040, 2975518758816, 9486517914720, 27053099888256, 70486130167488, 169930928938176, 384163702086528
Offset: 0

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Author

Keywords

Comments

Also the theta series of the Niemeier lattice of type E_6^4. - clarified by Ben Mares, Sep 13 2022

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

Crossrefs

Programs

  • Mathematica
    terms = 15; th = EllipticTheta; E4 = 1 + 240*Sum[k^3*(q^k/(1 - q^k)), {k, 1, terms}] + O[q]^terms; E6 = th[2, 0, q]^12 + th[3, 0, q]^12 - 33*th[2, 0, q]^4*th[3, 0, q]^4*(th[2, 0, q]^4 + th[3, 0, q]^4); CoefficientList[ (3/4)*E4^3 + (1/4)*E6^2 + O[q]^terms, q] (* Jean-François Alcover, Jul 05 2017 *)

Formula

This series is the q-expansion of (3*E_4(z)^3 + E_6(z)^2)/4. - Daniel D. Briggs, Nov 25 2011

A008696 Theta series of Niemeier lattice of type D_6^4.

Original entry on oeis.org

1, 240, 190800, 16833600, 397680720, 4630540320, 34416204480, 187485916800, 814900050000, 2975524213680, 9486523478880, 27053074226880, 70486147972800, 169930956669600, 384163682797440, 820166912933760
Offset: 0

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Author

Keywords

Comments

Also the theta series for the Niemeier lattice of type A_9^2 D_6. - clarified by Ben Mares, Sep 13 2022

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

Crossrefs

Programs

  • Mathematica
    terms = 15; th = EllipticTheta; E4 = 1 + 240*Sum[k^3*(q^k/(1 - q^k)), {k, 1, terms}] + O[q]^terms; E6 = th[2, 0, q]^12 + th[3, 0, q]^12 - 33*th[2, 0, q]^4*th[3, 0, q]^4*(th[2, 0, q]^4 + th[3, 0, q]^4); CoefficientList[ (13/18)*E4^3 + (5/18)*E6^2 + O[q]^terms, q] (* Jean-François Alcover, Jul 05 2017 *)

Formula

This series is the q-expansion of (13*E_4(z)^3 + 5*E_6(z)^2)/18. - Daniel D. Briggs, Nov 25 2011

A008700 Theta series of Niemeier lattice of type D_4^6.

Original entry on oeis.org

1, 144, 193104, 16809408, 397822032, 4630076640, 34416785088, 187487524224, 814891939920, 2975535123408, 9486534607200, 27053022904128, 70486183583424, 169931012132448, 384163644219264, 820166796086400
Offset: 0

Views

Author

Keywords

Comments

Also the theta series of the Niemeier lattice of type A_5^4 D_4. - clarified by Ben Mares, Jul 17 2022

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

Crossrefs

Programs

  • Mathematica
    terms = 15; th = EllipticTheta; E4 = 1 + 240*Sum[k^3*(q^k/(1 - q^k)), {k, 1, terms}] + O[q]^terms; E6 = th[2, 0, q]^12 + th[3, 0, q]^12 - 33*th[2, 0, q]^4*th[3, 0, q]^4*(th[2, 0, q]^4 + th[3, 0, q]^4); CoefficientList[ (2/3)*E4^3 + (1/3)*E6^2 + O[q]^terms, q] (* Jean-François Alcover, Jul 05 2017 *)

Formula

This series is the q-expansion of (2*E_4(z)^3 + E_6(z)^2)/3. - Daniel D. Briggs, Nov 25 2011

A008702 Theta series of Niemeier lattice of type A_3^8.

Original entry on oeis.org

1, 96, 194256, 16797312, 397892688, 4629844800, 34417075392, 187488327936, 814887884880, 2975540578272, 9486540171360, 27052997242752, 70486201388736, 169931039863872, 384163624930176
Offset: 0

Views

Author

Keywords

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.

Crossrefs

Programs

  • Mathematica
    terms = 15; E4[q_] := 1 + 240 Sum[DivisorSigma[3, n]*q^(2 n), {n, 1, terms}]; E6[q_] := 1 - 504 Sum[DivisorSigma[5, n]*q^(2 n), {n, 1, terms}]; s = 23/36 E4[q]^3 + 13/36 E6[q]^2 + O[q]^(3 terms); Partition[ CoefficientList[s, q], 2][[All, 1]][[1 ;; terms]] (* Jean-François Alcover, Jul 06 2017 *)

Formula

This series is the q-expansion of (23*E_4(z)^3 + 13*E_6(z)^2)/36. - Daniel D. Briggs, Nov 26 2011

A126858 Coefficients in quasimodular form F_2(q) of level 1 and weight 6.

Original entry on oeis.org

0, 0, 1, 8, 30, 80, 180, 336, 620, 960, 1590, 2200, 3416, 4368, 6440, 7920, 11160, 13056, 18333, 20520, 27860, 31360, 41052, 44528, 59760, 62400, 80990, 87120, 109872, 113680, 147960, 148800, 188976, 196416, 240210, 243040, 311910, 303696, 376580, 385840
Offset: 0

Views

Author

N. J. A. Sloane, Mar 15 2007

Keywords

Comments

This is also (5*E_2^3 - 3*E_2*E_4 - 2*E_6)/51840, where E_2, E_4, E_6 are the Eisenstein series shown in A006352, A004009, A013973, respectively. - N. J. A. Sloane, Feb 06 2017
This is also ((q*(d/dq)E_4)/240 + q*(d/dq)(q*(d/dq)E_2)/24)/6, where E_2 and E_4 are the Eisenstein series shown in A006352 and A004009, respectively. - Seiichi Manyama, Feb 08 2017

Examples

			F_2(q) = q^2 + 8*q^3 + 30*q^4 + 80*q^5 + 180*q^6 + 336*q^7 + 620*q^8 + 960*q^9 + 1590*q^10 + 2200*q^11 + ...
		

Crossrefs

Cf. A006352 (E_2), A004009 (E_4), A013973 (E_6), A145094 (q*(d/dq)E_4), A281372, A282097, A282154 (-q*(d/dq)(q*(d/dq)E_2)).

Programs

  • Maple
    with(numtheory); M:=100;
    E := proc(k) local n, t1; global M;
    t1 := 1-(2*k/bernoulli(k))*add(sigma[k-1](n)*q^n, n=1..M+1);
    series(t1, q, M+1); end;
    e2:=E(2); e4:=E(4); e6:=E(6);
    series((5*e2^3-3*e2*e4-2*e6)/51840,q,M+1);
    seriestolist(%); # from N. J. A. Sloane, Feb 06 2017
  • Mathematica
    terms = 40; Ei[n_] = 1 - (2 n/BernoulliB[n]) Sum[k^(n-1) x^k/(1-x^k), {k, 1, terms}]; S = 5 Ei[2]^3 - 3 Ei[2] Ei[4] - 2 Ei[6]; CoefficientList[S + O[x]^terms, x]/SeriesCoefficient[S, {x, 0, 2}] (* Jean-François Alcover, Feb 28 2018 *)
  • PARI
    {a(n) = local(L1, L2, L3); if( n<0, 0, L1 = 1 - 24 * sum( k = 1, n, sigma(k) * x^k, x * O(x^n)); L2 = x * L1'; L3 = x * L2'; polcoeff( (L1 * L2 - L3) / 720, n))} /* Michael Somos, Jan 08 2012 */

Formula

F_2(q) = (5*E(2)^3-3*E(2)*E(4)-2*E(6))/51840 where E(k) is the normalized Eisenstein series of weight k (cf. A006352, etc.).
Expansion of (L1 * L2 - L3) / 720 where L1 = E2 (A006352), L2 = q * dL1/dq, L3 = q * dL2/dq in powers of q where E2 is an Eisenstein series. - Michael Somos, Jan 08 2012
a(n) = (A145094(n)/240 - A282154(n)/24)/6 = (A281372(n) - A282097(n))/6. - Seiichi Manyama, Feb 08 2017

A186100 Expansion of 2 * a(q^2)^2 - a(q)^2 in powers of q where a() is a cubic AGM theta function.

Original entry on oeis.org

1, -12, -12, -12, -12, -72, -12, -96, -12, -12, -72, -144, -12, -168, -96, -72, -12, -216, -12, -240, -72, -96, -144, -288, -12, -372, -168, -12, -96, -360, -72, -384, -12, -144, -216, -576, -12, -456, -240, -168, -72, -504, -96, -528, -144, -72, -288
Offset: 0

Views

Author

Michael Somos, Feb 12 2011

Keywords

Comments

Cubic AGM theta functions: a(q) (see A004016), b(q) (A005928), c(q) (A005882).
Ramanujan theta functions: f(q) (see A121373), phi(q) (A000122), psi(q) (A010054), chi(q) (A000700).
Ramanujan's Eisenstein series: P(q) (see A006352), Q(q) (A004009), R(q) (A013973).

Examples

			G.f. = 1 - 12*q - 12*q^2 - 12*q^3 - 12*q^4 - 72*q^5 - 12*q^6 - 96*q^7 + ...
		

Crossrefs

Programs

  • Mathematica
    a[ n_] := If[ n < 1, Boole[n == 0], -12 DivisorSum[ n, # Boole[ 1 == GCD[#, 6]] &]]; (* Michael Somos, Jul 07 2015 *)
    a[ n_] := SeriesCoefficient[(EllipticTheta[ 4, 0, x] EllipticTheta[ 4, 0, x^3])^2 - 1/2 (EllipticTheta[ 2, 0, x^(1/2)] EllipticTheta[ 2, 0, x^(3/2)])^2, {x, 0, n}]; (* Michael Somos, Jul 07 2015 *)
  • PARI
    {a(n) = if( n<1, n==0, -12 * sumdiv( n, d, d * (1 == gcd( d, 6) ) ) )};
    
  • PARI
    {a(n) = if( n<1, n==0, -12 * direuler( p=2, n, 1 / (1 - X) / (1 - (p>3) * p * X)) [n])};

Formula

Expansion of b(x) * b(x^2) - c(x) * c(x^2) in powers of x where b(), c() are cubic AGM functions.
Expansion of (phi(-x) * phi(-x^3))^2 - 8 * x * (psi(x) * psi(x^3))^2 in powers of x where phi(), psi() are Ramanujan theta functions.
Expansion of (P(q) - 2*P(q^2) - 3*P(q^3) + 6*P(q^6)) / 2 in powers of q where P() is a Ramanujan Eisenstein series. - Michael Somos, Jul 07 2015
a(n) = -12 * A186099(n) if n>0. a(2*n) = a(n). a(2*n + 1) = - A008653(2*n + 1). a(n) = 2 * A008653(n) - A008653(2*n) = A131946(n) - 8 * A111932(n) = A131943(n) - 9 * A121443(n).
a(3*n) = a(n). a(6*n + 5) = -72 * A098098(n).- Michael Somos, Jul 07 2015

A341305 Fourier coefficients of the modular form (1/28)*(E_6(t)+27*E_6(3*t)).

Original entry on oeis.org

1, -18, -594, -4878, -19026, -56268, -160974, -302544, -608850, -1185858, -1856844, -2898936, -5156046, -6683292, -9983952, -15248628, -19483218, -25557444, -39133314, -44569800, -59475276, -81989424, -95664888, -115854192, -164998350, -175837518, -220548636, -288163998, -319789008, -369200700
Offset: 0

Views

Author

N. J. A. Sloane, Feb 13 2021

Keywords

Crossrefs

Cf. A013973.

Programs

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