A013973 -id:A013973 - cp's OEIS frontend

A289347 Coefficients in expansion of E_6^(3/4).

1, -378, -36288, -6664896, -1950813774, -672039262944, -253536117254784, -101485291597998336, -42360328701954544176, -18242860786892766495450, -8049299329628263783504512, -3621056234759774113947852096

Offset: 0

Seiichi Manyama, Jul 03 2017

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E_6^(k/12): A109817 (k=1), A289325 (k=2), A289326 (k=3), A289327 (k=4), A289328 (k=5), A289293 (k=6), A289345 (k=7), A289346 (k=8), this sequence (k=9), A289348 (k=10), A289349 (k=11).

Cf. A013973 (E_6), A288851.

nmax = 20; CoefficientList[Series[(1 - 504*Sum[DivisorSigma[5,k]*x^k, {k, 1, nmax}])^(3/4), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 08 2017 *)

G.f.: Product_{n>=1} (1-q^n)^(3*A288851(n)/4).

a(n) ~ c * exp(2*Pi*n) / n^(7/4), where c = -3^(5/2) * Gamma(1/4)^11 / (2048 * 2^(3/4) * Pi^9) = -0.21604472104032272720247495618663130188448925463945370445... - Vaclav Kotesovec, Jul 08 2017, updated Mar 05 2018

A289348 Coefficients in expansion of E_6^(5/6).

Original entry on oeis.org

1, -420, -31500, -4724160, -1314429900, -440028142344, -162555920654400, -63990327056960640, -26341675849615282380, -11210298679649742846180, -4895195936831699458605912, -2181913188022929464292248640

Offset: 0

Seiichi Manyama, Jul 03 2017

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E_6^(k/12): A109817 (k=1), A289325 (k=2), A289326 (k=3), A289327 (k=4), A289328 (k=5), A289293 (k=6), A289345 (k=7), A289346 (k=8), A289347 (k=9), this sequence (k=10), A289349 (k=11).

Cf. A013973 (E_6), A288851.

nmax = 20; CoefficientList[Series[(1 - 504*Sum[DivisorSigma[5,k]*x^k, {k, 1, nmax}])^(5/6), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 08 2017 *)

G.f.: Product_{n>=1} (1-q^n)^(5*A288851(n)/6).

a(n) ~ c * exp(2*Pi*n) / n^(11/6), where c = -5 * 3^(1/6) * Gamma(1/4)^(40/3) / (2048*sqrt(2) * Pi^(19/2) * Gamma(1/3)^2) = -0.1571123439957640423587958439875289712533650298096956968521099309872... - Vaclav Kotesovec, Jul 08 2017, updated Mar 05 2018

A289349 Coefficients in expansion of E_6^(11/12).

Original entry on oeis.org

1, -462, -24948, -2518824, -654112074, -212483064024, -76819071738024, -29728723632736128, -12066341379893331300, -5073593348593538950566, -2192302482140061697816872, -968086916154014421082349304, -435126775136273350146250044888

Offset: 0

Seiichi Manyama, Jul 03 2017

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In general, for 0 < m < 1, the expansion of (E_6)^m is asymptotic to -m * Gamma(1/4)^(16*m) * 3^(2*m) * exp(2*Pi*n) / (2^(13*m) * Pi^(12*m) * Gamma(1-m) * n^(1+m)). - Vaclav Kotesovec, Mar 05 2018

E_6^(k/12): A109817 (k=1), A289325 (k=2), A289326 (k=3), A289327 (k=4), A289328 (k=5), A289293 (k=6), A289345 (k=7), A289346 (k=8), A289347 (k=9), A289348 (k=10), this sequence (k=11).

Cf. A013973 (E_6), A288851.

nmax = 20; CoefficientList[Series[(1 - 504*Sum[DivisorSigma[5,k]*x^k, {k, 1, nmax}])^(11/12), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 08 2017 *)

G.f.: Product_{n>=1} (1-q^n)^(11*A288851(n)/12).

a(n) ~ c * exp(2*Pi*n) / n^(23/12), where c = -11 * 2^(5/12) * 3^(5/6) * Pi^(11/3) / (128 * Gamma(1/12) * Gamma(3/4)^(44/3)) = -0.08406022472181281739983743854923746657261382508944840919197295490535... - Vaclav Kotesovec, Jul 08 2017

A279892 Eisenstein series E_18(q) (alternate convention E_9(q)), multiplied by 43867.

Original entry on oeis.org

43867, -28728, -3765465144, -3709938631392, -493547047383096, -21917724609403728, -486272786232443616, -6683009405824511424, -64690198594597187640, -479102079577959825624, -2872821917728374840144, -14520482234727711482016, -63736746640768788267744

Offset: 0

Seiichi Manyama, Dec 22 2016

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J.-P. Serre, Course in Arithmetic, Chap. VII, Section 4.

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Cf. A006352 (E_2), A004009 (E_4), A013973 (E_6), A008410 (E_8), A013974 (E_10), A029828 (691*E_12), A058550 (E_14), A029829 (3617*E_16), this sequence (43867*E_18), A029830 (174611*E_20), A279893 (77683*E_22), A029831 (236364091*E_24).

Cf. A282000 (E_4^3*E_6), A282253 (E_6^3).

terms = 13;
E18[x_] = 43867 - 28728*Sum[k^17*x^k/(1 - x^k), {k, 1, terms}];
E18[x] + O[x]^terms // CoefficientList[#, x]& (* Jean-François Alcover, Feb 26 2018 *)

G.f.: 43867 - 28728 * Sum_{i>=1} sigma_17(i)q^i where sigma_17(n) is A013965.

a(n) = 38367*A282000(n) + 5500*A282253(n). - Seiichi Manyama, Feb 11 2017

A279893 Eisenstein series E_22(q) (alternate convention E_11(q)), multiplied by 77683.

Original entry on oeis.org

77683, -552, -1157628456, -5774114968608, -2427722831757864, -263214111328125552, -12109202528761173024, -308317316973972772416, -5091303792066668003880, -60399282006368937251976, -552000263214112485753456, -4084937969230504375869024, -25394838301602325644596256, -136379620048544616772836528, -646588586243917921590531648

Offset: 0

Seiichi Manyama, Dec 22 2016

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J.-P. Serre, Course in Arithmetic, Chap. VII, Section 4.

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Cf. A006352 (E_2), A004009 (E_4), A013973 (E_6), A008410 (E_8), A013974 (E_10), A029828 (691*E_12), A058550 (E_14), A029829 (3617*E_16), A279892 (43867*E_18), A029830 (174611*E_20), this sequence (77683*E_22), A029831 (236364091*E_24).

Cf. A282047 (E_4^4*E_6), A282328 (E_4*E_6^3).

terms = 15;
E22[x_] = 77683 - 552*Sum[k^21*x^k/(1 - x^k), {k, 1, terms}];
E22[x] + O[x]^terms // CoefficientList[#, x]& (* Jean-François Alcover, Feb 26 2018 *)

G.f.: 77683 - 552 * Sum_{i>=1} sigma_21(i)q^i where sigma_21(n) is A013969.

a(n) = 57183*A282047(n) + 20500*A282328(n). - Seiichi Manyama, Feb 12 2017

A028594 Expansion of (theta_3(q) * theta_3(q^7) + theta_2(q) * theta_2(q^7))^2 in powers of q.

Original entry on oeis.org

1, 4, 12, 16, 28, 24, 48, 4, 60, 52, 72, 48, 112, 56, 12, 96, 124, 72, 156, 80, 168, 16, 144, 96, 240, 124, 168, 160, 28, 120, 288, 128, 252, 192, 216, 24, 364, 152, 240, 224, 360, 168, 48, 176, 336, 312, 288, 192

Offset: 0

N. J. A. Sloane

nonn

Theta series of square of Kleinian lattice Z[ (-1+sqrt(-7))/2 ].
The Gram matrix of the lattice is denoted by A in Parry 1979 on page 163.
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).

			G.f. = 1 + 4*q + 12*q^2 + 16*q^3 + 28*q^4 + 24*q^5 + 48*q^6 + 4*q^7 + 60*q^8 + ...

B. C. Berndt, Ramanujan's Notebooks Part III, Springer-Verlag; see p. 467, Entry 5(i).

G. C. Greubel, Table of n, a(n) for n = 0..10000
W. R. Parry, A negative result on the representation of modular forms by theta series, J. Reine Angew. Math., 310 (1979), 151-170.
Michael Somos, Introduction to Ramanujan theta functions
Eric Weisstein's World of Mathematics, Ramanujan Theta Functions

Cf. A002652, A113957.

Basis( ModularForms( Gamma0(7), 2), 48) [1]; /* Michael Somos, Jun 12 2014 */

a[ n_] := If[ n < 1, Boole[ n == 0], 4 Sum[ If[ Mod[ d, 7] > 0, d, 0], {d, Divisors @ n }]]; (* Michael Somos, Jun 12 2014 *)
a[ n_] := SeriesCoefficient[ (EllipticTheta[ 3, 0, q] EllipticTheta[ 3, 0, q^7] + EllipticTheta[ 2, 0, q] EllipticTheta[ 2, 0, q^7])^2, {q, 0, n}]; (* Michael Somos, Jun 12 2014 *)

{a(n) = if( n<1, n==0, 4 * sigma( n / 7^valuation( n, 7)))}; /* Michael Somos, Oct 07 2005 */

{a(n) = if( n<1, n==0, 2 * qfrep( [2, 1, 0, 0; 1, 4, 0, 0; 0, 0, 2 ,1 ; 0, 0, 1, 4], n, 1)[n])}; /* Michael Somos, Oct 07 2005 */

{a(n) = if( n<1, n==0, 4 * sumdiv( n, d, d * kronecker( 49, d)))}; /* Michael Somos, Mar 22 2012 */

ModularForms( Gamma0(7), 2, prec=48).0; # Michael Somos, Jun 12 2014

Expansion of (phi(q) * phi(q^7) + 4 * q^2 * psi(q^2) * psi(q^14))^2 in powers of q where phi(), psi() are Ramanujan theta functions. - Michael Somos, Jul 21 2012
Expansion of (7 * P(q^7) - P(q)) / 6 where P() is a Ramanujan Eisenstein Series. - Michael Somos, Mar 22 2012
a(n) = 4 * b(n) where b(n) is multiplicative with b(p^e) = 1, if p=7, b(p^e) = (p^(e+1) - 1) / (p - 1) otherwise.
G.f. is a period 1 Fourier series which satisfies f(-1 / (7 t)) = 7 (t/i)^2 f(t) where q = exp(2 Pi i t). - Michael Somos, Mar 22 2012
G.f.: (theta_3(q) * theta_3(q^7) + theta_2(q) * theta_2(q^7))^2.
G.f.: 1 + 4 * (Sum_{k>0} Kronecker( 49, k) * k * x^k / (1 - x^k)). - Michael Somos, Mar 22 2012
G.f.: 1 + 4 * (Sum_{k>0} x^k / (1 - x^k)^2 - 7 * x^(7*k) / (1 - x^(7*k))^2). - Michael Somos, Mar 22 2012
Convolution square of A002652. a(n) = 4 * A113957(n) unless n=0. - Michael Somos, Jul 21 2012

A037947 Coefficients of unique normalized cusp form Delta_26 of weight 26 for full modular group.

Original entry on oeis.org

1, -48, -195804, -33552128, -741989850, 9398592, 39080597192, 3221114880, -808949403027, 35615512800, 8419515299052, 6569640870912, -81651045335314, -1875868665216, 145284580589400, 1125667983917056, -2519900028948078

Offset: 1

N. J. A. Sloane

sign

			q^2 - 48*q^4 - ...

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.

Seiichi Manyama, Table of n, a(n) for n = 1..1000
Fernando Q. Gouvêa, Non-ordinary primes: a story, Experimental Mathematics, Volume 6, Issue 3 (1997), 195-205.
S. C. Milne, Hankel determinants of Eisenstein series, preprint, arXiv:0009130 [math.NT], 2000.
Index entries for sequences related to modular groups

Cf. A000594 ((E_4(q)^3 - E_6(q)^2)/12^3), A004009 (E_4(q)), A013973 (E_6(q)), A290182.

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)*E6[x]*E4[x]^2 + O[x]^(terms+1) // CoefficientList[#, x]& // Rest (* Jean-François Alcover, Feb 27 2018, after Seiichi Manyama *)

G.f.: (E_4(q)^3 - E_6(q)^2)/12^3 * E_6(q) * E_4(q)^2. - Seiichi Manyama, Jun 09 2017

G.f.: -691*3617/(1728*2*3*5^3*7^2*13) * (E_10(q)*E_16(q) - E_12(q)*E_14(q)). - Seiichi Manyama, Jul 25 2017

A286346 Expansion of eta(q)^24 / eta(q^2)^12 in powers of q.

Original entry on oeis.org

1, -24, 264, -1760, 7944, -25872, 64416, -133056, 253704, -472760, 825264, -1297056, 1938336, -2963664, 4437312, -6091584, 8118024, -11368368, 15653352, -19822176, 24832944, -32826112, 42517728, -51425088, 61903776, -78146664, 98021616, -115331264, 133522752

Offset: 0

Seiichi Manyama, May 08 2017

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Seiichi Manyama, Table of n, a(n) for n = 0..10000
Simon Plouffe, Conjectures of the OEIS, as of June 20, 2018.

Cf. A000145, A013973 (E_6).

nmax = 20; CoefficientList[Series[Product[((1 - x^k)/(1 + x^k))^12, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 10 2018 *)
a[n_] := (-1)^n SquaresR[12, n];
a /@ Range[0, 30] (* Jean-François Alcover, Feb 21 2021 *)

q = 'q + O('q^50); Vec(eta(q)^24 / eta(q^2)^12) \\ Michel Marcus, Jul 07 2018

a(n) = (-1)^n * A000145(n).

Euler Transform of [-24, -12, -24, -12, -24, -12, -24, -12, ...]. - Simon Plouffe, Jun 23 2018

A290048 Coefficients in expansion of E_6*Delta^2 where Delta is the generating function of Ramanujan's tau function (A000594).

Original entry on oeis.org

1, -552, 8640, 116000, -4868460, 67855536, -544522240, 2742137280, -8237774250, 10592091400, 3366617856, 113971542048, -1217020425880, 4535746506000, -5415752171520, -19090509870144, 93580817811453, -142801363479240, -80721277168000, 665065363025280

Offset: 2

Seiichi Manyama, Jul 19 2017

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Seiichi Manyama, Table of n, a(n) for n = 2..1000
S. C. Milne, Hankel determinants of Eisenstein series, preprint, arXiv:0009130 [math.NT], 2000.

Cf. A000594, A010839, A013973 (E_6).
Cf. A282382, A282461 (E_6*E_10*E_14 = E_10^3), A290049, A290050.
E_k*Delta^2: A290178 (k=4), this sequence (k=6), A290180 (k=8), A290181 (k=10), A290182 (k=14).

terms = 20;
E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms}];
E6[x]*QPochhammer[x]^48 + O[x]^terms // CoefficientList[#, x]& (* Jean-François Alcover, Feb 26 2018 *)

Let b(q) be the determinant of the 3 X 3 Hankel matrix [E_6, E_8, E_10 ; E_8, E_10, E_12 ; E_10, E_12, E_14]. G.f. is -691^2*b(q)/(1728^2*250^2).

a(n) = (A290050(n) - 2*691*A290049(n) + 691^2*A282382(n))/(1728^2*250^2).

A008703 Theta series of Niemeier lattice of type A_2^12.

Original entry on oeis.org

1, 72, 194832, 16791264, 397928016, 4629728880, 34417220544, 187488729792, 814885857360, 2975543305704, 9486542953440, 27052984412064, 70486210291392, 169931053729584, 384163615285632

Offset: 0

N. J. A. Sloane

nonn

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

G. C. Greubel, Table of n, a(n) for n = 0..1000

Cf. A004009, A013973.

Cf. A008688 - A008702, A008704.

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 = 5/8 E4[q]^3 + 3/8 E6[q]^2 + O[q]^(3 terms); Partition[ CoefficientList[s, q], 2][[All, 1]][[1 ;; terms]] (* Jean-François Alcover, Jul 06 2017 *)

This series is the q-expansion of (5*E_4(z)^3 + 3*E_6(z)^2)/8. - Daniel D. Briggs, Nov 25 2011

cp's OEIS Frontend

A289347 Coefficients in expansion of E_6^(3/4).

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A289348 Coefficients in expansion of E_6^(5/6).

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A289349 Coefficients in expansion of E_6^(11/12).

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A279892 Eisenstein series E_18(q) (alternate convention E_9(q)), multiplied by 43867.

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A279893 Eisenstein series E_22(q) (alternate convention E_11(q)), multiplied by 77683.

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A028594 Expansion of (theta_3(q) * theta_3(q^7) + theta_2(q) * theta_2(q^7))^2 in powers of q.

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A037947 Coefficients of unique normalized cusp form Delta_26 of weight 26 for full modular group.

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A286346 Expansion of eta(q)^24 / eta(q^2)^12 in powers of q.

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