A290217 -id:A290217 - cp's OEIS frontend

A258210 Expansion of f(-q) * f(-q^2) * chi(-q^3) in powers of q where chi(), f() are Ramanujan theta functions.

1, -1, -2, 0, 1, 4, 0, 0, -2, -4, 2, 0, 0, -2, 0, 0, 1, 4, 4, 0, -4, 0, 0, 0, 0, -3, -4, 0, 0, 4, 0, 0, -2, 0, 2, 0, 4, -2, 0, 0, 2, 4, 0, 0, 0, -8, 0, 0, 0, -1, -6, 0, 2, 4, 0, 0, 0, 0, 2, 0, 0, -2, 0, 0, 1, 8, 0, 0, -4, 0, 0, 0, 4, -2, -4, 0, 0, 0, 0, 0, -4

Offset: 0

Michael Somos, May 23 2015

sign

Ramanujan theta functions: f(q) (see A121373), phi(q) (A000122), psi(q) (A010054), chi(q) (A000700).

Denoted by a_6(n) in Kassel and Reutenauer 2015. - Michael Somos, Jun 04 2015

			G.f. = 1 - q - 2*q^2 + q^4 + 4*q^5 - 2*q^8 - 4*q^9 + 2*q^10 - 2*q^13 + ...

Seiichi Manyama, Table of n, a(n) for n = 0..10000 (terms 0..1000 from G. C. Greubel)
Christian Kassel and Christophe Reutenauer, The zeta function of the Hilbert scheme of n points on a two-dimensional torus, arXiv:1505.07229v3 [math.AG], 2015 , see page 31 7.2(d). [Note that a later version of this paper has a different title and different contents, and the number-theoretical part of the paper was moved to the publication which is next in this list.]
Christian Kassel and Christophe Reutenauer, Complete determination of the zeta function of the Hilbert scheme of n points on a two-dimensional torus, arXiv:1610.07793 [math.NT], 2016, see p. 13 paragraph 3.3.4.
Christian Kassel, Christophe Reutenauer, The Fourier expansion of eta(z)eta(2z)eta(3z)/eta(6z), arXiv:1603.06357 [math.NT], 2016.
Michael Somos, Introduction to Ramanujan theta functions
Eric Weisstein's World of Mathematics, Ramanujan Theta Functions

Cf. A002175, A077285, A104794, A121444, A258228, A258277, A258278, A290217.

For the square of this series see A252650.

a[ n_] := SeriesCoefficient[ QPochhammer[ q]^2 / (QPochhammer[ q, q^6] QPochhammer[ q^5, q^6]), {q, 0, n}];
a[ n_] := SeriesCoefficient[ (1/2) EllipticThetaPrime[ 1, 0, q^(1/2)] / EllipticTheta[ 1, Pi/6, q^(1/2)], {q, 0, n}];

{a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x + A) * eta(x^2 + A) * eta(x^3 + A) / eta(x^6 + A), n))};

{a(n) = if( n<1, n==0, (-1)^n * (1 - (n%3==2)*3) * sumdiv(n, d, [0, 1, 2, -1][d%4 + 1] * if(d%9, 1, 4) * (-1)^((d%8==6) + n+d)))}; /* Michael Somos, Jun 04 2015 */

Expansion of f(-q)^2 * f(-q^6) / f(-q, -q^5) in powers of q where f(,) is Ramanujan's general theta function.
Expansion of eta(q) * eta(q^2) * eta(q^3) / eta(q^6) in powers of q.
Euler transform of period 6 sequence [ -1, -2, -2, -2, -1, -2, ...].
G.f. is a period 1 Fourier series which satisfies f(-1 / (72 t)) = 12 (t/i) g(t) where q = exp(2 Pi i t) and g() is the g.f. for A121444.
G.f.: Product_{k>0} (1 - x^k) * (1 - x^2*k) / (1 + x^(3*k)).
a(n) = (-1)^n * A258228(n). Convolution inverse of A077285.
a(4*n + 3) = 0. a(6*n + 2) = -2 * A122865(n). a(6*n + 4) = A122856(n). a(12*n + 1) = -1 * A002175(n).
a(9*n + 3) = a(9*n + 6) = 0. a(9*n) = A104794(n). a(3*n + 1) = -A258277(n). a(3*n + 2) = -2*A258278(n). - Michael Somos, May 01 2016
G.f.: Product_{i>0} 1/(1 + Sum_{j>0} j*x^(j*i)). - Seiichi Manyama, Oct 08 2017

A290216 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} jx^(ji)).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 3, 2, 0, 1, 1, 3, 2, 2, 0, 1, 1, 3, 5, 6, 3, 0, 1, 1, 3, 5, 6, 7, 4, 0, 1, 1, 3, 5, 10, 10, 12, 5, 0, 1, 1, 3, 5, 10, 10, 18, 13, 6, 0, 1, 1, 3, 5, 10, 15, 22, 25, 22, 8, 0, 1, 1, 3, 5, 10, 15, 22, 29, 34, 26, 10, 0, 1, 1, 3, 5

Offset: 0

Seiichi Manyama, Oct 06 2017

			Square array begins:
   1, 1, 1,  1,  1, ...
   0, 1, 1,  1,  1, ...
   0, 1, 3,  3,  3, ...
   0, 2, 2,  5,  5, ...
   0, 2, 6,  6, 10, ...
   0, 3, 7, 10, 10, ...

Seiichi Manyama, Antidiagonals n = 0..139, flattened

Columns k=0..3 give A000007, A000009, A293204, A290269.
Rows n=0 gives A000012.
Main diagonal gives A077285.
Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^m: A290217 (m=-1), this sequence (m=1), A293377 (m=2).
Cf. A293305.

A293377 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} jx^(ji))^2.

Original entry on oeis.org

1, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 7, 6, 0, 1, 2, 7, 10, 9, 0, 1, 2, 7, 16, 25, 14, 0, 1, 2, 7, 16, 31, 38, 22, 0, 1, 2, 7, 16, 39, 62, 78, 32, 0, 1, 2, 7, 16, 39, 70, 117, 116, 46, 0, 1, 2, 7, 16, 39, 80, 149, 206, 206, 66, 0, 1, 2, 7, 16, 39, 80, 159, 262, 362

Offset: 0

Seiichi Manyama, Oct 07 2017

			Square array begins:
   1,  1,  1,  1,  1, ...
   0,  2,  2,  2,  2, ...
   0,  3,  7,  7,  7, ...
   0,  6, 10, 16, 16, ...
   0,  9, 25, 31, 39, ...
   0, 14, 38, 62, 70, ...

Seiichi Manyama, Antidiagonals n = 0..139, flattened

Columns k=0..1 give A000007, A022567.
Rows n=0 gives A000012.
Main diagonal gives A293378.
Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^m: A290217 (m=-1), A290216 (m=1), this sequence (m=2).

A290395 G.f.: Product_{m>0} 1/(1 + x^m + 2x^(2m) + 3x^(3m)).

Original entry on oeis.org

1, -1, -2, 0, 5, 1, -12, -3, 31, 13, -64, -57, 139, 164, -285, -458, 560, 1217, -950, -3176, 1396, 7786, -1129, -18607, -2378, 43043, 17680, -96655, -67957, 208061, 217269, -429510, -628868, 836424, 1710935, -1497065, -4434111, 2294633, 11061661, -2348910

Offset: 0

Seiichi Manyama, Oct 06 2017

sign

Seiichi Manyama, Table of n, a(n) for n = 0..500

Column k=3 of A290217.

m = 30; Vec(prod(k=1, m, 1/(1 + x^k + 2*x^(2*k) + 3*x^(3*k))) + O(x^m)) \\ Michel Marcus, Oct 07 2017

A293386 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} 1/(1 + Sum_{j=1..k} jx^(ji))^2.

Original entry on oeis.org

1, 1, 0, 1, -2, 0, 1, -2, 1, 0, 1, -2, -3, -2, 0, 1, -2, -3, 10, 4, 0, 1, -2, -3, 4, -4, -4, 0, 1, -2, -3, 4, 14, -20, 5, 0, 1, -2, -3, 4, 6, -8, 41, -6, 0, 1, -2, -3, 4, 6, 16, -46, 2, 9, 0, 1, -2, -3, 4, 6, 6, -30, 14, -111, -12, 0, 1, -2, -3, 4, 6, 6, 0, -58

Offset: 0

Seiichi Manyama, Oct 07 2017

			Square array begins:
   1,  1,   1,  1,  1, ...
   0, -2,  -2, -2, -2, ...
   0,  1,  -3, -3, -3, ...
   0, -2,  10,  4,  4, ...
   0,  4,  -4, 14,  6, ...
   0, -4, -20, -8, 16, ...

Seiichi Manyama, Antidiagonals n = 0..139, flattened

Columns k=0..1 give A000007, A022597.
Rows n=0 gives A000012.
Main diagonal gives A252650.
Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^m: this sequence (m=-2), A290217 (m=-1), A290216 (m=1), A293377 (m=2).

cp's OEIS Frontend

A258210 Expansion of f(-q) * f(-q^2) * chi(-q^3) in powers of q where chi(), f() are Ramanujan theta functions.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Mathematica

PARI

PARI

Formula

A290216 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i)).

Views

Author

Keywords

Examples

Links

Crossrefs

A293377 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^2.

Views

Author

Keywords

Examples

Links

Crossrefs

A290395 G.f.: Product_{m>0} 1/(1 + x^m + 2*x^(2*m) + 3*x^(3*m)).

Views

Author

Keywords

Links

Crossrefs

Programs

PARI

A293386 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} 1/(1 + Sum_{j=1..k} j*x^(j*i))^2.

Views

Author

Keywords

Examples

Links

Crossrefs

A290216 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} jx^(ji)).

A293377 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} jx^(ji))^2.

A290395 G.f.: Product_{m>0} 1/(1 + x^m + 2x^(2m) + 3x^(3m)).

A293386 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} 1/(1 + Sum_{j=1..k} jx^(ji))^2.