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.

A337165 Number T(n,k) of compositions of n into k nonzero squares; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 0, 3, 0, 0, 1, 0, 0, 0, 0, 4, 0, 0, 1, 0, 0, 1, 0, 0, 5, 0, 0, 1, 0, 1, 0, 3, 0, 0, 6, 0, 0, 1, 0, 0, 2, 0, 6, 0, 0, 7, 0, 0, 1, 0, 0, 0, 3, 0, 10, 0, 0, 8, 0, 0, 1, 0, 0, 0, 1, 4, 0, 15, 0, 0, 9, 0, 0, 1
Offset: 0

Views

Author

Alois P. Heinz, Feb 03 2021

Keywords

Examples

			Triangle T(n,k) begins:
  1;
  0, 1;
  0, 0, 1;
  0, 0, 0, 1;
  0, 1, 0, 0, 1;
  0, 0, 2, 0, 0,  1;
  0, 0, 0, 3, 0,  0,  1;
  0, 0, 0, 0, 4,  0,  0, 1;
  0, 0, 1, 0, 0,  5,  0, 0, 1;
  0, 1, 0, 3, 0,  0,  6, 0, 0, 1;
  0, 0, 2, 0, 6,  0,  0, 7, 0, 0, 1;
  0, 0, 0, 3, 0, 10,  0, 0, 8, 0, 0, 1;
  0, 0, 0, 1, 4,  0, 15, 0, 0, 9, 0, 0, 1;
  ...
		

Crossrefs

Row sums give A006456.
T(2n,n) gives A338464.
Main diagonal gives A000012.

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, 1, add((s->
         `if`(s>n, 0, expand(x*b(n-s))))(j^2), j=1..isqrt(n)))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n)):
    seq(T(n), n=0..14);
  • Mathematica
    b[n_] := b[n] = If[n == 0, 1, Sum[With[{s = j^2},
         If[s>n, 0, Expand[x*b[n - s]]]], {j, 1, Sqrt[n]}]];
    T[n_] := CoefficientList[b[n], x];
    T /@ Range[0, 14] // Flatten (* Jean-François Alcover, Feb 07 2021, after Alois P. Heinz *)

Formula

G.f. of column k: (Sum_{j>=1} x^(j^2))^k.
Sum_{k=0..n} k * T(n,k) = A281704(n).
Sum_{k=0..n} (-1)^k * T(n,k) = A317665(n).

A340905 Number of ways to write n as an ordered sum of 6 squares of positive integers.

Original entry on oeis.org

1, 0, 0, 6, 0, 0, 15, 0, 6, 20, 0, 30, 15, 0, 60, 12, 15, 60, 31, 60, 30, 60, 90, 36, 86, 60, 120, 120, 15, 180, 141, 60, 165, 140, 180, 186, 120, 180, 285, 156, 126, 360, 255, 216, 270, 260, 390, 240, 262, 420, 426, 360, 210, 540, 530, 216, 540, 540, 480, 600, 300, 600, 825, 312, 576, 840
Offset: 6

Views

Author

Ilya Gutkovskiy, Jan 31 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
          `if`(s>n, 0, b(n-s, t-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n, 6):
    seq(a(n), n=6..71);  # Alois P. Heinz, Jan 31 2021
  • Mathematica
    nmax = 71; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^6/64, {x, 0, nmax}], x] // Drop[#, 6] &

Formula

G.f.: (theta_3(x) - 1)^6 / 64, where theta_3() is the Jacobi theta function.

A340481 Number of ways to write n as an ordered sum of 5 squares of positive integers.

Original entry on oeis.org

1, 0, 0, 5, 0, 0, 10, 0, 5, 10, 0, 20, 5, 0, 30, 6, 10, 20, 20, 30, 5, 30, 30, 20, 35, 10, 60, 45, 0, 60, 50, 30, 45, 50, 60, 70, 35, 30, 110, 50, 31, 110, 80, 80, 50, 70, 120, 70, 75, 90, 140, 110, 20, 140, 160, 60, 135, 120, 120, 180, 40, 130, 230, 80, 120, 170, 200, 155, 85, 200, 190
Offset: 5

Views

Author

Ilya Gutkovskiy, Jan 31 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
          `if`(s>n, 0, b(n-s, t-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n, 5):
    seq(a(n), n=5..75);  # Alois P. Heinz, Jan 31 2021
  • Mathematica
    nmax = 75; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^5/32, {x, 0, nmax}], x] // Drop[#, 5] &

Formula

G.f.: (theta_3(x) - 1)^5 / 32, where theta_3() is the Jacobi theta function.

A340906 Number of ways to write n as an ordered sum of 7 squares of positive integers.

Original entry on oeis.org

1, 0, 0, 7, 0, 0, 21, 0, 7, 35, 0, 42, 35, 0, 105, 28, 21, 140, 49, 105, 105, 106, 210, 84, 182, 210, 217, 287, 105, 420, 378, 126, 497, 392, 420, 532, 350, 630, 714, 434, 546, 980, 742, 609, 980, 896, 1071, 882, 875, 1470, 1239, 1099, 1155, 1722, 1652, 882, 1933, 1995, 1554, 2072, 1505
Offset: 7

Views

Author

Ilya Gutkovskiy, Jan 31 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
          `if`(s>n, 0, b(n-s, t-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n, 7):
    seq(a(n), n=7..67);  # Alois P. Heinz, Jan 31 2021
  • Mathematica
    nmax = 67; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^7/128, {x, 0, nmax}], x] // Drop[#, 7] &

Formula

G.f.: (theta_3(x) - 1)^7 / 128, where theta_3() is the Jacobi theta function.

A340915 Number of ways to write n as an ordered sum of 8 squares of positive integers.

Original entry on oeis.org

1, 0, 0, 8, 0, 0, 28, 0, 8, 56, 0, 56, 70, 0, 168, 64, 28, 280, 84, 168, 280, 176, 420, 224, 345, 560, 392, 616, 420, 848, 924, 336, 1246, 1064, 868, 1464, 988, 1680, 1820, 1120, 1904, 2464, 1932, 1904, 2870, 2752, 2772, 2912, 2892, 4256, 3640, 3248, 4480, 5040, 4760, 3696, 6120
Offset: 8

Views

Author

Ilya Gutkovskiy, Jan 31 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
          `if`(s>n, 0, b(n-s, t-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n, 8):
    seq(a(n), n=8..64);  # Alois P. Heinz, Jan 31 2021
  • Mathematica
    nmax = 64; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^8/256, {x, 0, nmax}], x] // Drop[#, 8] &

Formula

G.f.: (theta_3(x) - 1)^8 / 256, where theta_3() is the Jacobi theta function.

A340947 Number of ways to write n as an ordered sum of 10 squares of positive integers.

Original entry on oeis.org

1, 0, 0, 10, 0, 0, 45, 0, 10, 120, 0, 90, 210, 0, 360, 262, 45, 840, 300, 360, 1260, 480, 1260, 1350, 1015, 2520, 1560, 2200, 3150, 2880, 4186, 2880, 5430, 6240, 3780, 8300, 7080, 7920, 11160, 7320, 13257, 14640, 10600, 16470, 18570, 18240, 19620, 22230, 25135, 27720, 28020, 28480, 38160
Offset: 10

Views

Author

Ilya Gutkovskiy, Jan 31 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, t) option remember;
          `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
          `if`(s>n, 0, b(n-s, t-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n, 10):
    seq(a(n), n=10..62);  # Alois P. Heinz, Jan 31 2021
  • Mathematica
    nmax = 62; CoefficientList[Series[(EllipticTheta[3, 0, x] - 1)^10/1024, {x, 0, nmax}], x] // Drop[#, 10] &

Formula

G.f.: (theta_3(x) - 1)^10 / 1024, where theta_3() is the Jacobi theta function.

A025444 Number of partitions of n into 5 distinct nonzero squares.

Original entry on oeis.org

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

Views

Author

Keywords

Examples

			a(111) = 2 via 1 + 4 + 9 + 16 + 81 = 1 + 9 + 16 + 36 + 49. - _David A. Corneth_, Feb 02 2021
		

Crossrefs

Programs

  • Maple
    From R. J. Mathar, Oct 18 2010: (Start)
    A025444aux := proc(n,m,nmax) local a,m,upn,lv ; if m = 1 then if issqr(n) and nmax^2 >= n and n >= 1 then return 1; else return 0; end if; else a := 0 ; for upn from 1 to nmax do lv := n-upn^2 ; if lv <0 then break; end if; a := a + procname(lv,m-1,upn-1) ; end do: return a; end if; end proc:
    A025444 := proc(n) A025444aux(n,5,n) ; end proc: (End)

Formula

a(n) = [x^n y^5] Product_{k>=1} (1 + y*x^(k^2)). - Ilya Gutkovskiy, Apr 22 2019

A341370 Expansion of (1 / theta_4(x) - 1)^9 / 512.

Original entry on oeis.org

1, 18, 180, 1311, 7740, 39204, 176388, 721530, 2728053, 9651056, 32246892, 102515508, 311923386, 912771468, 2579132196, 7060677537, 18781247700, 48660380190, 123061973176, 304351869708, 737293187286, 1752035386188, 4089222211212, 9384936015492, 21201250825554
Offset: 9

Views

Author

Ilya Gutkovskiy, Feb 10 2021

Keywords

Crossrefs

Programs

  • Maple
    g:= proc(n, i) option remember; `if`(n=0, 1/2, `if`(i=1, 0,
          g(n, i-1))+add(2*g(n-i*j, i-1), j=`if`(i=1, n, 1)..n/i))
        end:
    b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0,
          g(n$2)), (q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
        end:
    a:= n-> b(n, 9):
    seq(a(n), n=9..33);  # Alois P. Heinz, Feb 10 2021
  • Mathematica
    nmax = 33; CoefficientList[Series[(1/EllipticTheta[4, 0, x] - 1)^9/512, {x, 0, nmax}], x] // Drop[#, 9] &
    nmax = 33; CoefficientList[Series[(1/512) (-1 + Product[(1 + x^k)/(1 - x^k), {k, 1, nmax}])^9, {x, 0, nmax}], x] // Drop[#, 9] &

Formula

G.f.: (1/512) * (-1 + Product_{k>=1} (1 + x^k) / (1 - x^k))^9.

A341000 Number of partitions of n into 9 distinct nonzero squares.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 2, 0, 0, 0, 1, 2, 0, 0, 2
Offset: 285

Views

Author

Ilya Gutkovskiy, Feb 02 2021

Keywords

Examples

			a(381) = 2 via 1 + 4 + 9 + 16 + 36 + 49 + 64 + 81 + 121 = 1 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100. - _David A. Corneth_, Feb 02 2021
		

Crossrefs

A341428 Number of positive solutions to (x_1)^2 + (x_2)^2 + ... + (x_9)^2 <= n^2.

Original entry on oeis.org

1, 46, 760, 7751, 43910, 186098, 652710, 1943742, 5178030, 12411211, 27773308, 57798904, 114152429, 214399664, 387571706, 673189698, 1135916808, 1857320784, 2966816950, 4623984661, 7066527283, 10577150039, 15589368584, 22580091614, 32256768126
Offset: 3

Views

Author

Ilya Gutkovskiy, Feb 11 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, k) option remember; `if`(k=0, 1, `if`(n=0, 0,
          add((s->`if`(s>n, 0, b(n-s, k-1)))(j^2), j=1..isqrt(n))))
        end:
    a:= n-> b(n^2, 9):
    seq(a(n), n=3..27);  # Alois P. Heinz, Feb 11 2021
  • Mathematica
    Table[SeriesCoefficient[(EllipticTheta[3, 0, x] - 1)^9/(512 (1 - x)), {x, 0, n^2}], {n, 3, 27}]

Formula

a(n) is the coefficient of x^(n^2) in expansion of (theta_3(x) - 1)^9 / (512 * (1 - x)).
Showing 1-10 of 10 results.