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 11 results. Next

A053283 Coefficients of the '10th-order' mock theta function X(q).

Original entry on oeis.org

1, -1, 1, 0, 1, -2, 1, -1, 1, -2, 3, -1, 2, -4, 3, -2, 3, -5, 4, -4, 5, -6, 7, -5, 6, -9, 9, -7, 9, -12, 11, -11, 12, -15, 16, -14, 16, -21, 20, -18, 22, -25, 26, -25, 28, -33, 34, -33, 35, -42, 43, -41, 47, -53, 53, -54, 57, -65, 69, -67, 73, -83, 85, -83, 92, -102, 104, -106, 114, -125, 130, -130, 139, -154
Offset: 0

Views

Author

Dean Hickerson, Dec 19 1999

Keywords

References

  • Srinivasa Ramanujan, The Lost Notebook and Other Unpublished Papers, Narosa Publishing House, New Delhi, 1988, p. 9

Crossrefs

Other '10th-order' mock theta functions are at A053281, A053282, A053284.

Programs

  • Mathematica
    Series[Sum[(-1)^n q^n^2/Product[1+q^k, {k, 1, 2n}], {n, 0, 10}], {q, 0, 100}]
    nmax = 100; CoefficientList[Series[Sum[(-1)^k * x^(k^2) / Product[1+x^j, {j, 1, 2*k}], {k, 0, Floor[Sqrt[nmax]]}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 11 2019 *)

Formula

G.f.: X(q) = Sum_{n >= 0} (-1)^n q^n^2/((1+q)(1+q^2)...(1+q^(2n))).
a(n) ~ (-1)^n * exp(Pi*sqrt(n/10)) / (2*5^(1/4)*sqrt(phi*n)), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Jun 12 2019

A053281 Coefficients of the '10th-order' mock theta function phi(q).

Original entry on oeis.org

1, 2, 2, 3, 4, 4, 6, 7, 8, 10, 12, 14, 16, 20, 22, 26, 31, 34, 40, 46, 52, 60, 68, 76, 87, 98, 110, 124, 140, 156, 174, 196, 216, 242, 270, 298, 332, 368, 406, 449, 496, 546, 602, 664, 728, 800, 880, 962, 1056, 1156, 1262, 1381, 1508, 1644, 1794, 1956, 2128
Offset: 0

Views

Author

Dean Hickerson, Dec 19 1999

Keywords

Comments

The alternating sum of the same series, namely phi(q) = Sum_{n>=0} (-1)^n q^(n(n+1)/2)/((1-q)(1-q^3)...(1-q^(2n+1))) = 1 + x^3 - x^7 - x^16 + x^24 + x^39 - x^51 - ..., where the exponents are given by 5n^2 +- 2n. See the Amer. Math. Monthly reference.

References

  • Srinivasa Ramanujan, The Lost Notebook and Other Unpublished Papers, Narosa Publishing House, New Delhi, 1988, p. 9.

Crossrefs

Other '10th-order' mock theta functions are at A053282, A053283, A053284.

Programs

  • Mathematica
    Series[Sum[q^(n(n+1)/2)/Product[1-q^(2k+1), {k, 0, n}], {n, 0, 13}], {q, 0, 100}]
    nmax = 100; CoefficientList[Series[Sum[x^(k*(k+1)/2) / Product[1-x^(2*j+1), {j, 0, k}], {k, 0, Floor[Sqrt[2*nmax]]}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 11 2019 *)

Formula

G.f.: phi(q) = Sum_{n >= 0} q^(n(n+1)/2)/((1-q)(1-q^3)...(1-q^(2n+1))).
a(n) ~ sqrt(phi) * exp(Pi*sqrt(n/5)) / (2*5^(1/4)*sqrt(n)), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Jun 12 2019

A053284 Coefficients of the '10th-order' mock theta function chi(q).

Original entry on oeis.org

0, 1, -1, 1, -2, 2, -1, 2, -3, 3, -3, 3, -4, 4, -4, 5, -6, 7, -6, 7, -9, 8, -8, 10, -12, 13, -13, 13, -16, 17, -16, 19, -21, 22, -23, 25, -28, 29, -30, 33, -37, 39, -39, 42, -48, 49, -50, 55, -60, 64, -66, 70, -77, 81, -82, 89, -97, 101, -105, 112, -121, 126, -131, 140, -151, 159, -163, 173, -187, 194, -202
Offset: 0

Views

Author

Dean Hickerson, Dec 19 1999

Keywords

References

  • Srinivasa Ramanujan, The Lost Notebook and Other Unpublished Papers, Narosa Publishing House, New Delhi, 1988, p. 9.

Crossrefs

Other '10th-order' mock theta functions are at A053281, A053282, A053283.

Programs

  • Mathematica
    Series[Sum[(-1)^n q^(n+1)^2/Product[1+q^k, {k, 1, 2n+1}], {n, 0, 9}], {q, 0, 100}]
    nmax = 100; CoefficientList[Series[Sum[(-1)^k * x^((k+1)^2)/Product[1+x^j, {j, 1, 2*k+1}], {k, 0, Floor[Sqrt[nmax]]}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 11 2019 *)

Formula

G.f.: chi(q) = Sum_{n >= 0} (-1)^n q^(n+1)^2/((1+q)(1+q^2)...(1+q^(2n+1))).
a(n) ~ -(-1)^n * sqrt(phi) * exp(Pi*sqrt(n/10)) / (2*5^(1/4)*sqrt(n)), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Jun 12 2019

A304705 Number of partitions (d1,d2,...,dm) of n such that d1/1 >= d2/2 >= ... >= dm/m and 0 < d1 <= d2 <= ... <= dm.

Original entry on oeis.org

1, 1, 2, 3, 3, 4, 6, 5, 6, 8, 9, 9, 12, 11, 14, 17, 16, 17, 23, 22, 27, 31, 30, 33, 40, 41, 46, 50, 54, 57, 70, 70, 77, 88, 92, 99, 111, 115, 129, 142, 152, 160, 175, 183, 199, 223, 234, 255, 283, 299, 328, 347, 370, 390, 430, 455, 489, 523, 557, 592, 642, 674, 724, 784
Offset: 0

Views

Author

Seiichi Manyama, May 17 2018

Keywords

Examples

			n | Partition (d1,d2,...,dm)    | (d1/1, d2/2, ... , dm/m)
--+-----------------------------+---------------------------------------------
1 | (1)                         | (1)
2 | (2)                         | (2)
  | (1, 1)                      | (1, 1/2)
3 | (3)                         | (3)
  | (1, 2)                      | (1, 1)
  | (1, 1, 1)                   | (1, 1/2, 1/3)
4 | (4)                         | (4)
  | (2, 2)                      | (2, 1)
  | (1, 1, 1, 1)                | (1, 1/2, 1/3, 1/4)
5 | (5)                         | (5)
  | (2, 3)                      | (2, 3/2)
  | (1, 2, 2)                   | (1, 1, 2/3)
  | (1, 1, 1, 1, 1)             | (1, 1/2, 1/3, 1/4, 1/5)
6 | (6)                         | (6)
  | (2, 4)                      | (2, 2)
  | (3, 3)                      | (3, 3/2)
  | (1, 2, 3)                   | (1, 1, 1)
  | (2, 2, 2)                   | (2, 1, 2/3)
  | (1, 1, 1, 1, 1, 1)          | (1, 1/2, 1/3, 1/4, 1/5, 1/6)
7 | (7)                         | (7)
  | (3, 4)                      | (3, 2)
  | (2, 2, 3)                   | (2, 1, 1)
  | (1, 2, 2, 2)                | (1, 1, 2/3, 1/2)
  | (1, 1, 1, 1, 1, 1, 1)       | (1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7)
8 | (8)                         | (8)
  | (3, 5)                      | (3, 5/2)
  | (4, 4)                      | (4, 2/1)
  | (2, 3, 3)                   | (2, 3/2, 1)
  | (2, 2, 2, 2)                | (2, 1, 2/3, 1/2)
  | (1, 1, 1, 1, 1, 1, 1, 1)    | (1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8)
9 | (9)                         | (9)
  | (3, 6)                      | (3, 3)
  | (4, 5)                      | (4, 5/2)
  | (2, 3, 4)                   | (2, 3/2, 4/3)
  | (3, 3, 3)                   | (3, 3/2, 1)
  | (1, 2, 3, 3)                | (1, 1, 1, 3/4)
  | (1, 2, 2, 2, 2)             | (1, 1, 2/3, 1/2, 2/5)
  | (1, 1, 1, 1, 1, 1, 1, 1, 1) | (1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8, 1/9)
		

Crossrefs

Programs

  • Maple
    b:= proc(n, r, i, t) option remember; `if`(n=0, 1, `if`(i>n, 0,
          b(n, r, i+1, t)+`if`(i/t>r, 0, b(n-i, i/t, i, t+1))))
        end:
    a:= n-> b(n$2, 1$2):
    seq(a(n), n=0..80);  # Alois P. Heinz, May 17 2018
  • Mathematica
    b[n_, r_, i_, t_] := b[n, r, i, t] = If[n == 0, 1, If[i > n, 0, b[n, r, i + 1, t] + If[i/t > r, 0, b[n - i, i/t, i, t + 1]]]];
    a[n_] := b[n, n, 1, 1];
    a /@ Range[0, 80] (* Jean-François Alcover, Nov 23 2020, after Alois P. Heinz *)

A304706 Number of partitions (d1,d2,...,dm) of n such that d1/1 > d2/2 > ... > dm/m and 0 < d1 <= d2 <= ... <= dm.

Original entry on oeis.org

1, 1, 2, 2, 3, 3, 4, 3, 6, 5, 6, 6, 8, 7, 11, 10, 11, 12, 15, 14, 18, 17, 20, 23, 27, 25, 31, 32, 35, 38, 43, 43, 51, 54, 59, 63, 71, 73, 85, 89, 96, 102, 113, 120, 134, 141, 149, 161, 175, 183, 203, 213, 233, 252, 280, 293, 319, 338, 360, 383, 409, 430, 468, 493, 531, 565
Offset: 0

Views

Author

Seiichi Manyama, May 17 2018

Keywords

Examples

			n | Partition (d1,d2,...,dm)    | (d1/1, d2/2, ... , dm/m)
--+-----------------------------+---------------------------------------------
1 | (1)                         | (1)
2 | (2)                         | (2)
  | (1, 1)                      | (1, 1/2)
3 | (3)                         | (3)
  | (1, 1, 1)                   | (1, 1/2, 1/3)
4 | (4)                         | (4)
  | (2, 2)                      | (2, 1)
  | (1, 1, 1, 1)                | (1, 1/2, 1/3, 1/4)
5 | (5)                         | (5)
  | (2, 3)                      | (2, 3/2)
  | (1, 1, 1, 1, 1)             | (1, 1/2, 1/3, 1/4, 1/5)
6 | (6)                         | (6)
  | (3, 3)                      | (3, 3/2)
  | (2, 2, 2)                   | (2, 1, 2/3)
  | (1, 1, 1, 1, 1, 1)          | (1, 1/2, 1/3, 1/4, 1/5, 1/6)
7 | (7)                         | (7)
  | (3, 4)                      | (3, 2)
  | (1, 1, 1, 1, 1, 1, 1)       | (1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7)
8 | (8)                         | (8)
  | (3, 5)                      | (3, 5/2)
  | (4, 4)                      | (4, 2/1)
  | (2, 3, 3)                   | (2, 3/2, 1)
  | (2, 2, 2, 2)                | (2, 1, 2/3, 1/2)
  | (1, 1, 1, 1, 1, 1, 1, 1)    | (1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8)
9 | (9)                         | (9)
  | (4, 5)                      | (4, 5/2)
  | (2, 3, 4)                   | (2, 3/2, 4/3)
  | (3, 3, 3)                   | (3, 3/2, 1)
  | (1, 1, 1, 1, 1, 1, 1, 1, 1) | (1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8, 1/9)
		

Crossrefs

Programs

  • Maple
    b:= proc(n, r, i, t) option remember; `if`(n=0, 1, `if`(i>n, 0,
          b(n, r, i+1, t)+`if`(i/t>=r, 0, b(n-i, i/t, i, t+1))))
        end:
    a:= n-> b(n, n+1, 1$2):
    seq(a(n), n=0..80);  # Alois P. Heinz, May 17 2018
  • Mathematica
    b[n_, r_, i_, t_] := b[n, r, i, t] = If[n == 0, 1, If[i > n, 0, b[n, r, i + 1, t] + If[i/t >= r, 0, b[n - i, i/t, i, t + 1]]]];
    a[n_] := b[n, n + 1, 1, 1];
    a /@ Range[0, 80] (* Jean-François Alcover, Nov 23 2020, after Alois P. Heinz *)

Formula

a(n) <= A304705(n).

A304707 Number of partitions (d1,d2,...,dm) of n such that d1/1 >= d2/2 >= ... >= dm/m and d1 < d2 < ... < dm.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 2, 2, 4, 3, 4, 5, 4, 5, 7, 5, 7, 8, 8, 10, 12, 10, 11, 14, 14, 14, 18, 17, 20, 23, 22, 26, 30, 29, 32, 35, 34, 37, 43, 44, 48, 54, 54, 59, 67, 70, 76, 81, 84, 89, 97, 101, 110, 119, 123, 129, 139, 145, 155, 171, 176, 189, 201, 211, 228, 245, 257, 274, 295
Offset: 0

Views

Author

Seiichi Manyama, May 17 2018

Keywords

Examples

			n | Partition (d1,d2,...,dm)    | (d1/1, d2/2, ... , dm/m)
--+-----------------------------+-------------------------
1 | (1)                         | (1)
2 | (2)                         | (2)
3 | (3)                         | (3)
  | (1, 2)                      | (1, 1)
4 | (4)                         | (4)
5 | (5)                         | (5)
  | (2, 3)                      | (2, 3/2)
6 | (6)                         | (6)
  | (2, 4)                      | (2, 2)
  | (1, 2, 3)                   | (1, 1, 1)
7 | (7)                         | (7)
  | (3, 4)                      | (3, 2)
8 | (8)                         | (8)
  | (3, 5)                      | (3, 5/2)
9 | (9)                         | (9)
  | (3, 6)                      | (3, 3)
  | (4, 5)                      | (4, 5/2)
  | (2, 3, 4)                   | (2, 3/2, 4/3)
		

Crossrefs

Programs

  • Maple
    b:= proc(n, r, i, t) option remember; `if`(n=0, 1, `if`(i>n, 0,
          b(n, r, i+1, t) +`if`(i/t>r, 0, b(n-i, i/t, i+1, t+1))))
        end:
    a:= n-> b(n$2, 1$2):
    seq(a(n), n=0..80);  # Alois P. Heinz, May 17 2018
  • Mathematica
    b[n_, r_, i_, t_] := b[n, r, i, t] = If[n == 0, 1, If[i > n, 0, b[n, r, i + 1, t] + If[i/t > r, 0, b[n - i, i/t, i + 1, t + 1]]]];
    a[n_] := b[n, n, 1, 1];
    a /@ Range[0, 80] (* Jean-François Alcover, Nov 23 2020, after Alois P. Heinz *)

A304708 Number of partitions (d1,d2,...,dm) of n such that d1/1 > d2/2 > ... > dm/m and d1 < d2 < ... < dm.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 2, 2, 3, 2, 3, 3, 3, 5, 5, 4, 5, 6, 6, 7, 8, 8, 9, 10, 12, 11, 13, 13, 16, 16, 15, 18, 21, 22, 26, 25, 28, 31, 33, 33, 35, 39, 41, 46, 47, 50, 53, 59, 63, 68, 74, 77, 84, 90, 93, 98, 105, 111, 119, 129, 132, 138, 149, 157, 169, 178, 189, 201, 211, 227
Offset: 0

Views

Author

Seiichi Manyama, May 17 2018

Keywords

Examples

			n | Partition (d1,d2,...,dm)    | (d1/1, d2/2, ... , dm/m)
--+-----------------------------+-------------------------
1 | (1)                         | (1)
2 | (2)                         | (2)
3 | (3)                         | (3)
4 | (4)                         | (4)
5 | (5)                         | (5)
  | (2, 3)                      | (2, 3/2)
6 | (6)                         | (6)
7 | (7)                         | (7)
  | (3, 4)                      | (3, 2)
8 | (8)                         | (8)
  | (3, 5)                      | (3, 5/2)
9 | (9)                         | (9)
  | (4, 5)                      | (4, 5/2)
  | (2, 3, 4)                   | (2, 3/2, 4/3)
		

Crossrefs

Programs

  • Maple
    b:= proc(n, r, i, t) option remember; `if`(n=0, 1, `if`(i>n, 0,
          b(n, r, i+1, t)+`if`(i/t>=r, 0, b(n-i, i/t, i+1, t+1))))
        end:
    a:= n-> b(n, n+1, 1$2):
    seq(a(n), n=0..80);  # Alois P. Heinz, May 17 2018
  • Mathematica
    b[n_, r_, i_, t_] := b[n, r, i, t] = If[n == 0, 1, If[i > n, 0, b[n, r, i + 1, t] + If[i/t >= r, 0, b[n - i, i/t, i + 1, t + 1]]]];
    a[n_] := b[n, n + 1, 1, 1];
    a /@ Range[0, 80] (* Jean-François Alcover, Nov 23 2020, after Alois P. Heinz *)

Formula

a(n) <= A304707(n).

A376624 G.f.: Sum_{k>=0} x^(k*(k+1)/2) / Product_{j=1..k} (1 - x^(2*j-1))^2.

Original entry on oeis.org

1, 1, 2, 4, 6, 8, 13, 18, 23, 33, 44, 57, 77, 99, 125, 163, 207, 259, 328, 407, 503, 626, 769, 938, 1149, 1397, 1687, 2044, 2458, 2943, 3531, 4213, 5011, 5957, 7055, 8334, 9838, 11580, 13594, 15948, 18661, 21790, 25425, 29593, 34386, 39918, 46250, 53501, 61824, 71325
Offset: 0

Views

Author

Vaclav Kotesovec, Sep 30 2024

Keywords

Crossrefs

Programs

  • Mathematica
    nmax=60; CoefficientList[Series[Sum[x^(k*(k+1)/2)/Product[1-x^(2*j-1), {j, 1, k}]^2, {k, 0, Sqrt[2*nmax]}], {x, 0, nmax}], x]

Formula

G.f.: Sum_{k>=0} Product_{j=1..k} x^j/(1 - x^(2*j-1))^2.
a(n) ~ (r^(3/4)/sqrt(8*(1 + 3*r^2))) * A376658^sqrt(n) / sqrt(n), where r = A072223 = 0.52488859865640479389948613854128391569... is the smallest real root of the equation (1 - r^2)^2 = r.

A376628 G.f.: Sum_{k>=0} x^(k*(k+1)) / Product_{j=1..k} (1 - x^(2*j-1)).

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 5, 5, 5, 7, 7, 8, 10, 10, 12, 14, 15, 17, 19, 21, 23, 27, 29, 31, 37, 39, 43, 49, 52, 58, 64, 70, 76, 84, 92, 99, 111, 119, 129, 143, 153, 167, 183, 197, 213, 233, 251, 271, 295, 317, 343, 372, 400, 430, 466, 500, 538, 582, 622, 670
Offset: 0

Views

Author

Vaclav Kotesovec, Sep 30 2024

Keywords

Crossrefs

Programs

  • Mathematica
    nmax=100; CoefficientList[Series[Sum[x^(k*(k+1))/Product[1-x^(2*j-1), {j, 1, k}], {k, 0, Sqrt[nmax]}], {x, 0, nmax}], x]

Formula

G.f.: Sum_{k>=0} Product_{j=1..k} x^(2*j)/(1 - x^(2*j-1)).
a(n) ~ exp(Pi*sqrt(n/6)) / (2^(5/2) * sqrt(n)).
Conjectural g.f.: (1 + q * nu(-q))/(1 + q) = 1 + Sum_{k >= 0} q^(k+2)*Product_{j = 1..k} 1 + q^(2*j+1), where nu(q) is the g.f. of A053254. - Peter Bala, Jan 03 2025

A304869 Triangle read by rows: T(n, k) gives the number of partitions (d1,d2,...,dk) of n such that 0 < d1/1 <= d2/2 <= ... <= dk/k for 1 <= k <= A003056(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 3, 2, 1, 3, 2, 1, 1, 3, 3, 1, 1, 4, 4, 1, 1, 4, 4, 2, 1, 4, 5, 2, 1, 5, 6, 3, 1, 1, 5, 7, 4, 1, 1, 5, 8, 5, 1, 1, 6, 9, 6, 2, 1, 6, 10, 7, 2, 1, 6, 11, 9, 3, 1, 7, 13, 10, 4, 1, 1, 7, 14, 12, 5, 1, 1, 7, 15, 14, 6, 1
Offset: 1

Views

Author

Seiichi Manyama, May 20 2018

Keywords

Examples

			The partitions (d1,d2) of 9 such that 0 < d1/1 <= d2/2 are (1, 8), (2, 7) and (3, 6). So T(9, 2) = 3.
First few rows are:
  1;
  1;
  1, 1;
  1, 1;
  1, 1;
  1, 2, 1;
  1, 2, 1;
  1, 2, 1;
  1, 3, 2;
  1, 3, 2, 1;
  1, 3, 3, 1;
  1, 4, 4, 1;
  1, 4, 4, 2;
  1, 4, 5, 2;
  1, 5, 6, 3, 1;
		

Crossrefs

Row sums give A053282.
Cf. A304871.
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