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 1-7 of 7 results.

A288851 Exponents a(1), a(2), ... such that E_6, 1 - 504*q - 16632*q^2 - ... (A013973) is equal to (1-q)^a(1) (1-q^2)^a(2) (1-q^3)^a(3) ... .

Original entry on oeis.org

504, 143388, 51180024, 20556578700, 8806299845112, 3929750661380124, 1803727445909594616, 845145871847732769804, 402283166289266872824312, 193877350835487271784566812, 94381548697864188120110027256, 46328820782943001597184984563596
Offset: 1

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Author

Seiichi Manyama, Jun 18 2017

Keywords

Crossrefs

Cf. A288968 (k=2), A110163 (k=4), this sequence (k=6), A288471 (k=8), A289024 (k=10), A288990/A288989 (k=12), A289029 (k=14).
Cf. A008683, A013973 (E_6), A110163, A288840 (E_8/E_6), A289637.

Formula

a(n) = A013975(n^2) for n>=1.
a(n) = 12 + (1/(2*n)) * Sum_{d|n} A008683(n/d) * A288840(d).
a(n) = (1/n) * Sum_{d|n} A008683(n/d) * A289637(d). - Seiichi Manyama, Jul 09 2017
a(n) ~ exp(2*Pi*n) / n. - Vaclav Kotesovec, Mar 08 2018

A110163 Exponents a(1), a(2), ... such that theta series of E_8 lattice, 1 + 240 q + 2160 q^2 + ... (A004009) is equal to (1-q)^a(1) (1-q^2)^a(2) (1-q^3)^a(3) ...

Original entry on oeis.org

-240, 26760, -4096240, 708938760, -130880766192, 25168873498760, -4978357936128240, 1005225129317834760, -206195878414962688240, 42824436296045618358408, -8983966738037593190400240, 1900416270294787067711818760, -404814256845771786255876096240, 86744167089111545378556727322760
Offset: 1

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Author

N. J. A. Sloane, Sep 16 2005

Keywords

Comments

Negative of inverse Euler transform of [240, 2160, ...].

Examples

			From _Seiichi Manyama_, Jun 17 2017: (Start)
a(1) = 8 + 1/3 * A008683(1/1) * A288261(1) = 8 + 1/3 * (-744) = -240,
a(2) = 8 + 1/6 * (A008683(2/1) * A288261(1) + A008683(2/2) * A288261(2)) = 8 + 1/6 * (744 + 159768) = 26760. (End)
		

Crossrefs

Cf. A288968 (k=2), this sequence (k=4), A288851 (k=6), A288471 (k=8), A289024 (k=10), A288990/A288989 (k=12), A289029 (k=14).

Programs

  • Mathematica
    terms = 14; Clear[a, sol];
    a4009[n_] := If[n == 0, 1, 240 DivisorSigma[3, n]];
    sol[0] = {}; sol[kmax_] := sol[kmax] = Join[sol[kmax-1], SolveAlways[ Sum[ a4009[k] q^k, {k, 0, kmax}] == Normal[Product[(1-q^k)^a[k], {k, 1, kmax}] + O[q]^(kmax+1)] /. sol[kmax-1], q][[1]] ];
    A110163 = Array[a, terms] /. sol[terms] (* Jean-François Alcover, Jul 03 2017 *)

Formula

a(n) = A013953(n^2) for n>=1. - Seiichi Manyama, Jun 17 2017
a(n) = 8 + (1/(3*n)) * Sum_{d|n} A008683(n/d) * A288261(d). - Seiichi Manyama, Jun 17 2017
a(n) = (1/n) * Sum_{d|n} A008683(n/d) * A289636(d). - Seiichi Manyama, Jul 09 2017
a(n) ~ (-1)^n * exp(Pi*sqrt(3)*n) / n. - Vaclav Kotesovec, Mar 08 2018

A288968 Exponents a(1), a(2), ... such that E_2, 1 - 24*q - 72*q^2 - ... (A006352) is equal to (1-q)^a(1) (1-q^2)^a(2) (1-q^3)^a(3) ... .

Original entry on oeis.org

24, 348, 6424, 129300, 2778648, 62114524, 1428337176, 33527349924, 799482197272, 19302454317660, 470740035601176, 11575875047000596, 286650683468840472, 7140515309818664028, 178783562850377621272, 4496350112540599930692
Offset: 1

Views

Author

Seiichi Manyama, Jun 20 2017

Keywords

Crossrefs

Cf. this sequence (k=2), A110163 (k=4), A288851 (k=6), A288471 (k=8), A289024 (k=10), A288990/A288989 (k=12), A289029 (k=14).
Cf. A006352 (E_2), A008683, A288877 (E_4/E_2), A289635.

Formula

a(n) = 2 + (1/(12*n)) * Sum_{d|n} A008683(n/d) * A288877(d).
a(n) = (1/n) * Sum_{d|n} A008683(n/d) * A289635(d).
a(n) ~ 1 / (n * r^(2*n)), where r = A057823. - Vaclav Kotesovec, Mar 08 2018

A289029 Exponents a(1), a(2), ... such that E_14, 1 - 24*q - 196632*q^2 + ... (A058550) is equal to (1-q)^a(1) (1-q^2)^a(2) (1-q^3)^a(3) ... .

Original entry on oeis.org

24, 196908, 42987544, 21974456220, 8544538312728, 3980088408377644, 1793770730037338136, 847156322106368439324, 401870774532436947447832, 193962999708079363021283628, 94363580764388112933729226776, 46332621615483591171320408201116
Offset: 1

Views

Author

Seiichi Manyama, Jun 22 2017

Keywords

Comments

This sequence is related to the identity: E_4^2*E_6 = E_4*E_10 = E_6*E_8 = E_14.

Crossrefs

Cf. A288968 (k=2), A110163 (k=4), A288851 (k=6), A288471 (k=8), A289024 (k=10), A288990/A288989 (k=12), this sequence (k=14).
Cf. A008683, A288261 (E_6/E_4), A288840 (E_8/E_6), A289640.

Formula

a(n) = 2 * A110163(n) + A288851(n) = A110163(n) + A289024(n) = A288851(n) + A288471(n) = 28 + (1/n) * (Sum_{d|n} A008683(n/d) * (2/3 * A288261(d) + 1/2 * A288840(d))).
a(n) = (1/n) * Sum_{d|n} A008683(n/d) * A289640(d). - Seiichi Manyama, Jul 09 2017
a(n) ~ exp(2*Pi*n) / n. - Vaclav Kotesovec, Mar 08 2018

A289024 Exponents a(1), a(2), ... such that E_10, 1 - 264*q - 135432*q^2 + ... (A013974) is equal to (1-q)^a(1) (1-q^2)^a(2) (1-q^3)^a(3) ... .

Original entry on oeis.org

264, 170148, 47083784, 21265517460, 8675419078920, 3954919534878884, 1798749087973466376, 846151096977050604564, 402076970410851910136072, 193920175271783317402925220, 94372564731126150526919627016, 46330721199213296384252696382356
Offset: 1

Views

Author

Seiichi Manyama, Jun 22 2017

Keywords

Comments

This sequence is related to the identity: E_4*E_6 = E_10.

Crossrefs

Cf. A288968 (k=2), A110163 (k=4), A288851 (k=6), A288471 (k=8), this sequence (k=10), A288990/A288989 (k=12), A289029 (k=14).
Cf. A008683, A288261 (E_6/E_4), A288840 (E_8/E_6), A289639.

Formula

a(n) = A110163(n) + A288851(n) = 20 + (1/n) * (Sum_{d|n} A008683(n/d) * (1/3 * A288261(d) + 1/2 * A288840(d))).
a(n) = (1/n) * Sum_{d|n} A008683(n/d) * A289639(d). - Seiichi Manyama, Jul 09 2017
a(n) ~ exp(2*Pi*n) / n. - Vaclav Kotesovec, Mar 08 2018

A289638 Coefficients in expansion of -q*E'_8/E_8 where E_8 is the Eisenstein Series (A008410).

Original entry on oeis.org

-480, 106560, -24577920, 5671616640, -1308807662400, 302026457514240, -69697011105795840, 16083602074756972800, -3711525811469352966240, 856488725919603559612800, -197647268236827050188805760, 45609990487075191657212674560
Offset: 1

Views

Author

Seiichi Manyama, Jul 09 2017

Keywords

Crossrefs

-q*E'_k/E_k: A289635 (k=2), A289636 (k=4), A289637 (k=6), this sequence (k=8), A289639 (k=10), A289640 (k=14).
Cf. A006352 (E_2), A008410 (E_8), A287933, A288471.

Programs

  • Mathematica
    nmax = 20; Rest[CoefficientList[Series[-480*x*Sum[k*DivisorSigma[7, k]*x^(k-1), {k, 1, nmax}]/(1 + 480*Sum[DivisorSigma[7, k]*x^k, {k, 1, nmax}]), {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 09 2017 *)

Formula

a(n) = Sum_{d|n} d * A288471(d).
a(n) = 2*A288261(n)/3 + 16*A000203(n).
a(n) = -Sum_{k=1..n-1} A008410(k)*a(n-k) - A008410(n)*n.
G.f.: 2/3 * E_6/E_4 - 2/3 * E_2 = 2/3 * E_10/E_8 - 2/3 * E_2.
a(n) ~ 2 * (-1)^n * exp(Pi*sqrt(3)*n). - Vaclav Kotesovec, Jul 09 2017

A288990 Define the exponents b(1), b(2), ... such that E_12 is equal to (1-q)^b(1) (1-q^2)^b(2) (1-q^3)^b(3) ... . a(n) = b(n) * A288989(n).

Original entry on oeis.org

-65520, -90598009320, 442356959924880, 4181653887366701917080, -42458488603945952980072176, -254774947034575235293755006524520, 3880639008647135220484579615019041680, 17460929863645555627595091312548802016985880
Offset: 1

Views

Author

Seiichi Manyama, Jun 21 2017

Keywords

Examples

			b(1) = 24 + 1/1 * A008683(1/1) * A288472(1)/A288989(1) = 24 + 1/1 * (-82104/691) = -65520/691,
b(2) = 24 + 1/2 * (A008683(2/1) * A288472(1)/A288989(1) + A008683(2/2) * A288472(2)/A288989(2)) = 24 + 1/2 * (82104/691 - 181275671592/477481) = -90598009320/477481.
		

Crossrefs

Cf. A288989.
Cf. A288968 (k=2), A110163 (k=4), A288851 (k=6), A288471 (k=8).

Formula

b(n) = a(n)/A288989(n) = 24 + (1/n) * Sum_{d|n} A008683(n/d) * A288472(d)/A288989(d).
Showing 1-7 of 7 results.