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 1-10 of 10 results.

A328532 G.f. = Phi^5*F, where Phi = g.f. for A028930, F = g.f. for A028959.

Original entry on oeis.org

1, 2, 10, 30, 72, 180, 394, 760, 1474, 2552, 4312, 6764, 10664, 15290, 22764, 31252, 44134, 58360, 80192, 101988, 135852, 169552, 218968, 267170, 340142, 406342, 507626, 600242, 735996, 856054, 1042952, 1193878, 1435032, 1633492, 1943892, 2185304
Offset: 0

Views

Author

N. J. A. Sloane, Oct 18 2019

Keywords

References

  • Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See p. 196. (A028930 is Phi_1, A028959 is F_1.)

Crossrefs

A328533 G.f. = Phi^4*F^2, where Phi = g.f. for A028930, F = g.f. for A028959.

Original entry on oeis.org

1, 4, 12, 40, 100, 216, 472, 896, 1580, 2732, 4408, 6816, 10400, 15280, 22000, 31088, 43308, 58072, 78804, 102176, 134056, 169408, 218320, 268228, 339768, 409244, 507744, 603368, 738000, 859424, 1041376, 1200664, 1435908, 1639184, 1943224, 2186656
Offset: 0

Views

Author

N. J. A. Sloane, Oct 18 2019

Keywords

References

  • Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See p. 196. (A028930 is Phi_1, A028959 is F_1.)

Crossrefs

A328534 G.f. = Phi^3*F^3, where Phi = g.f. for A028930, F = g.f. for A028959.

Original entry on oeis.org

1, 6, 18, 50, 132, 276, 530, 1008, 1710, 2760, 4464, 6828, 10268, 15246, 21828, 30820, 42750, 57696, 77032, 101916, 132564, 169736, 216816, 269286, 338490, 412386, 507354, 605278, 739308, 865314, 1042944, 1207962, 1437132, 1643508, 1943628, 2191176
Offset: 0

Views

Author

N. J. A. Sloane, Oct 18 2019

Keywords

References

  • Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See p. 196. (A028930 is Phi_1, A028959 is F_1.)

Crossrefs

A328535 G.f. = Phi^2*F^4, where Phi = g.f. for A028930, F = g.f. for A028959.

Original entry on oeis.org

1, 8, 28, 68, 160, 344, 608, 1032, 1784, 2836, 4416, 6928, 10348, 15260, 21848, 30112, 42012, 57312, 76308, 101272, 131648, 169064, 215496, 270344, 335484, 415128, 506736, 608908, 738976, 873268, 1045160, 1214468, 1437016, 1648432, 1946832, 2201072
Offset: 0

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Author

N. J. A. Sloane, Oct 18 2019

Keywords

References

  • Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See p. 196. (A028930 is Phi_1, A028959 is F_1.)

Crossrefs

A328536 G.f. = Phi*F^5, where Phi = g.f. for A028930, F = g.f. for A028959.

Original entry on oeis.org

1, 10, 42, 102, 192, 372, 682, 1064, 1706, 2936, 4680, 7084, 10384, 14786, 21564, 30260, 41094, 57288, 76368, 99540, 130972, 167168, 214984, 271402, 333430, 414590, 507546, 613482, 738364, 881518, 1041144, 1225406, 1437184, 1656212, 1951012, 2215480
Offset: 0

Views

Author

N. J. A. Sloane, Oct 18 2019

Keywords

References

  • Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See p. 196. (A028930 is Phi_1, A028959 is F_1.)

Crossrefs

A030199 Expansion of x * Product_{k>=1} (1 - x^k) * (1 - x^(23*k)).

Original entry on oeis.org

1, -1, -1, 0, 0, 1, 0, 1, 0, 0, 0, 0, -1, 0, 0, -1, 0, 0, 0, 0, 0, 0, 1, -1, 1, 1, 1, 0, -1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, -1, -1, 1, 1, -1, 0, 0, 0, -1, 0, 0, 0, 1, 2, 0, 0, 1, 0, 1, 0, 0, 0, 0, -1, 0, -1, 0, -1, 0, -1, 0, 0, -1, 0, 0, -1
Offset: 1

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Keywords

Comments

Number 40 of the 74 eta-quotients listed in Table I of Martin (1996).

Examples

			G.f. = q - q^2 - q^3 + q^6 + q^8 - q^13 - q^16 + q^23 - q^24 + q^25 + q^26 + ...
		

Crossrefs

Programs

  • Magma
    Basis( CuspForms( Gamma1(23), 1), 82) [1]; /* Michael Somos, Sep 08 2014 */
  • Mathematica
    a[ n_] := SeriesCoefficient[ q QPochhammer[ q] QPochhammer[ q^23], {q, 0, n}]; (* Michael Somos, May 17 2015 *)
  • PARI
    {a(n) = my(A); if( n<1, 0, n--; A = x * O(x^n); polcoeff( eta(x + A) * eta(x^23 + A), n))}; /* Michael Somos, May 02 2005 */
    
  • PARI
    {a(n) = my(A, p, e, y); if( n<1, 0, A = factor(n); prod( k=1, matsize(A)[1], [p, e] = A[k, ]; if( p==23, 1, y = sum( x=1, p-1, (x^3 - x - 1)%p == 0); if( y==1, 1-e%2, y, e+1, (e-1)%3 - 1))))}; /* Michael Somos, Oct 19 2005 */
    
  • PARI
    {a(n) = if( n<1, 0, qfrep([2, 1; 1, 12], n, 1)[n] - qfrep([4, 1; 1, 6], n, 1)[n])}; /* Michael Somos, Sep 08 2014 */
    
  • PARI
    {a(n) = if( n<1, 0, mfcoefs(mfeigenbasis(mfinit([23, 1, Mod(22, 23)], 0))[1], n)[n+1])}; /* Michael Somos, Aug 22 2025 */
    

Formula

Expansion of eta(q) * eta(q^23) in powers of q.
Euler transform of period 23 sequence [ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, ...]. - Michael Somos, May 02 2005
G.f. A(x) satisfies 0 = f(A(x), A(x^2), A(x^4)) where f(u, v, w) = -v^3 + 2 *u * v * w + 2 * u * w^2 + u^2 * w. - Michael Somos, May 02 2005
G.f. A(x) satisfies 0 = f(A(x), A(x^2), A(x^3), A(x^6)) where f(u1, u2, u3, u6) = u1^2 * u3 * u6 +2 * u1 * u2 * u3 * u6 - 2 * u1 * u6^3 + 2 * u2^2 * u3 * u6 - u2 * u3^3. - Michael Somos, May 02 2005
a(n) is multiplicative with a(23^e) = 1. Let y = number of zeros of x^3 - x - 1 modulo p, then a(p^e) = (1 + (-1)^e)/2 if y = 1, a(p^e) = e+1 if y = 3, a(p^e) = (e-1)%3 - 1 if y = 0. - Michael Somos, Oct 19 2005
a(8*n + 4) = a(23*n + 5) = a(23*n + 7) = a(23*n + 10) = a(23*n + 11) = a(23*n + 14) = a(23*n + 15) = a(23*n + 19) = a(23*n + 20) = a(23*n + 21) = a(23*n + 22) = 0. - Michael Somos, Oct 19 2005
G.f. is a period 1 Fourier series which satisfies f(-1 / (23 t)) = 23^(1/2) (t/i) f(t) where q = exp(2 Pi i t). - Michael Somos, Sep 08 2014
2 * a(n) = A028959(n) - A028930(n). - Michael Somos, Sep 08 2014

Extensions

Reference to Martin and Ono added by Chandan Singh Dalawat (dalawat(AT)gmail.com), Jul 23 2010

A028958 Numbers represented by quadratic form with Gram matrix [ 2, 1; 1, 12 ] (divided by 2).

Original entry on oeis.org

0, 1, 4, 6, 8, 9, 12, 16, 18, 23, 24, 25, 26, 27, 32, 36, 39, 48, 49, 52, 54, 58, 59, 62, 64, 72, 78, 81, 82, 87, 92, 93, 94, 96, 100, 101, 104, 108, 116, 117, 121, 123, 124, 128, 138, 141, 142, 144, 146, 150, 156, 162, 164, 167, 169, 173, 174, 184, 186, 188, 192
Offset: 1

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Keywords

Comments

Nonnegative integers of the form x^2 + x*y + 6*y^2, discriminant -23. - Ray Chandler, Jul 12 2014
The Gram matrix is positive-definite, therefore, if w := (1 + sqrt(-23)) / 2, then |x + w*y|^2 = x^2 + x*y + 6*y^2 > 0 for all integers x and y except x = y = 0. - Michael Somos, Mar 28 2015
The theta function of the lattice with basis [1, w] is the g.f. of A028959, therefore, A028959(n) is positive if and only if n is in this sequence. - Michael Somos, Mar 28 2015

Crossrefs

For primes see A033217. Cf. A028929, A106867.
Cf. A028959.

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Mar 29 2000

A328093 Expansion of (theta_3(z)*theta_3(23z) + theta_2(z)*theta_2(23z))^5.

Original entry on oeis.org

1, 10, 40, 80, 90, 112, 260, 480, 700, 1050, 1520, 2160, 2980, 3920, 5920, 8160, 9530, 12800, 16620, 20560, 26672, 30720, 38960, 47690, 52020, 66250, 77380, 87940, 101600, 112720, 134304, 147920, 171020, 185760, 220160, 230400, 263550, 292080, 341200, 346820, 423984, 425680, 516480, 527600, 619120
Offset: 0

Views

Author

N. J. A. Sloane, Oct 17 2019

Keywords

References

  • Köklüce, Bülent. "Cusp forms in S_6 (Gamma_ 0(23)), S_8 (Gamma_0 (23)) and the number of representations of numbers by some quadratic forms in 12 and 16 variables." The Ramanujan Journal 34.2 (2014): 187-208. See F_k, p. 188.

Crossrefs

Programs

  • PARI
    a(n) = polcoeff((1 + 2*x*Ser(qfrep([2, 1; 1, 12], n, 1)))^5, n); \\ Jinyuan Wang, Feb 19 2020

A328094 Expansion of (theta_3(z)*theta_3(23z) + theta_2(z)*theta_2(23z))^6.

Original entry on oeis.org

1, 12, 60, 160, 252, 312, 568, 1200, 2004, 3036, 4680, 7008, 10264, 14568, 21024, 31280, 42012, 54408, 75284, 99600, 129912, 168688, 210240, 272460, 336048, 404052, 516432, 618224, 736272, 884712, 1033008, 1244976, 1439820, 1666800, 1953288, 2232000, 2548516, 2893848, 3376224, 3756912, 4294344
Offset: 0

Views

Author

N. J. A. Sloane, Oct 17 2019

Keywords

Crossrefs

Programs

  • PARI
    a(n) = polcoeff((1 + 2*x*Ser(qfrep([2, 1; 1, 12], n, 1)))^6, n); \\ Jinyuan Wang, Feb 20 2020

A224529 Sequence f_n from a paper by Robert Osburn and Brundaban Sahu.

Original entry on oeis.org

1, 2, 6, 26, 142, 876, 5790, 40020, 285582, 2087612, 15551620, 117629724, 900964558, 6973745924, 54464010540, 428645647572, 3396238954446, 27067890450300, 216857021933172, 1745460025192140, 14107695302434356, 114455036696796168, 931738743735004596
Offset: 0

Views

Author

Joerg Arndt, Apr 09 2013

Keywords

Comments

Conjecture 1.1 of Osburn and Sahu is if p is a prime and JacobiSymbol(p, 23) = 1 and n>0 then a(n * p) == a(n) (mod p). - Michael Somos, Sep 21 2013

Examples

			G.f. = 1 + 2*x + 6*x^2 + 26*x^3 + 142*x^4 + 876*x^5 + 5790*x^6 + 40020*x^7 + ...
		

Crossrefs

Cf. A224530 (sequence F_n).

Programs

  • Maple
    p := (1+224*x -864*x^2 -544*x^3 +9664*x^4 -26112*x^5 +36288*x^6 -27648*x^7 +9216*x^8) ;
    s := (1-14*x+57*x^2-106*x^3+90*x^4-16*x^5-19*x^6)^(1/2) ;
    A := (5*(53-400*x+944*x^2-912*x^3+288*x^4)-24*(11-16*x)*s)/p ;
    f := 4*x*(1-45*x+865*x^2-9270*x^3+60648*x^4 -249463*x^5+640904*x^6 -987056*x^7 +821224*x^8-249920*x^9 -71232*x^10+20610*x^11 -(1-21*x +148*x^2 -380*x^3+212*x^4)*(1-17*x+90*x^2-142*x^3 -14*x^4)*s)*(6*A)^3/23^6;
    ogf := A^(1/4) * hypergeom([1/12, 5/12],[1], f);
    series(ogf, x=0, 101);  # Mark van Hoeij, Apr 12 2014
  • Mathematica
    a[ n_] := If[ n < 0, 0, With[ {f = Series[ EllipticTheta[ 3, 0, x] EllipticTheta[ 3, 0, x^23] + EllipticTheta[ 2, 0, x] EllipticTheta[ 2, 0, x^23], {x, 0, n}], g = x QPochhammer[ x] QPochhammer[ x^23]}, SeriesCoefficient[ ComposeSeries[ f, InverseSeries[ g/f ]], {x, 0, n}]]]; (* Michael Somos, Sep 21 2013 *)

Formula

n^2 * a(n) = (14*n^2 - 21*n + 9) * a(n-1) + (-57*n^2 + 171*n - 136) * a(n-2) + (106*n^2 - 477*n + 551) * a(n-3) + (-90*n^2 + 540*n - 816) * a(n-4) + (16*n^2 - 120*n + 224) * a(n-5) + (19*n^2 - 171*n + 380) * a(n-6). - Michael Somos, Sep 21 2013
G.f. A(x) satisfies f(q) = A(g(q)) where f is the g.f. for A028959 and g(q) = eta(q) * eta(q^23) / f(q). - Michael Somos, Sep 21 2013
Showing 1-10 of 10 results.