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 1-5 of 5 results.

A151760 G.f.: Theta^4, where Theta = Sum_{k>=0} x^(2^k).

Original entry on oeis.org

0, 0, 0, 0, 1, 4, 6, 8, 13, 12, 10, 16, 18, 16, 20, 24, 13, 12, 18, 16, 22, 24, 28, 24, 18, 16, 28, 24, 20, 24, 24, 0, 13, 12, 18, 16, 30, 24, 28, 24, 22, 24, 36, 24, 28, 24, 24, 0, 18, 16, 28, 24, 28, 24, 24, 0, 20, 24, 24, 0, 24, 0, 0, 0, 13, 12, 18, 16, 30, 24, 28, 24, 30, 24, 36
Offset: 0

Views

Author

N. J. A. Sloane, Jun 22 2009

Keywords

Comments

Number of ways to write n as an ordered sum of 4 powers of 2. - Ilya Gutkovskiy, Feb 02 2021

Crossrefs

Cf. A151758.

Programs

  • Maple
    N:= 10: # for a(0) .. a(2^N)
    g:= add(x^(2^i),i=0..N)^4:
    S:= series(g,x,2^N+1):
    seq(coeff(S,x,j),j=0..2^N); # Robert Israel, Mar 27 2020

A151759 G.f.: Theta^3, where Theta = Sum_{k>=0} x^(2^k).

Original entry on oeis.org

0, 0, 0, 1, 3, 3, 4, 6, 3, 3, 6, 6, 4, 6, 6, 0, 3, 3, 6, 6, 6, 6, 6, 0, 4, 6, 6, 0, 6, 0, 0, 0, 3, 3, 6, 6, 6, 6, 6, 0, 6, 6, 6, 0, 6, 0, 0, 0, 4, 6, 6, 0, 6, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 3, 3, 6, 6, 6, 6, 6, 0, 6, 6, 6, 0, 6, 0, 0, 0, 6, 6, 6, 0, 6, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 4, 6, 6, 0, 6, 0, 0, 0, 6
Offset: 0

Views

Author

N. J. A. Sloane, Jun 22 2009

Keywords

Comments

Number of ways to write n as an ordered sum of 3 powers of 2. - Ilya Gutkovskiy, Feb 02 2021

Crossrefs

(Sum_{k>=0} x^(2^k))^m; A209229 (m=1), A073267 (m=2), this sequence (m=3), A151760 (m=4), A151761 (m=5), A151762 (m=6).

Programs

  • Maple
    b:= proc(n, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
          `if`(t<1, 0, add(b(n-2^j, t-1), j=0..ilog2(n))))
        end:
    a:= n-> b(n, 3):
    seq(a(n), n=0..104);  # Alois P. Heinz, Feb 02 2021
  • Mathematica
    b[n_, t_] := b[n, t] = If[n == 0, If[t == 0, 1, 0],
         If[t < 1, 0, Sum[b[n - 2^j, t - 1], {j, 0, Floor@Log2[n]}]]];
    a[n_] := b[n, 3];
    Table[a[n], {n, 0, 104}] (* Jean-François Alcover, Mar 08 2022, after Alois P. Heinz *)

A151761 G.f.: Theta^5, where Theta = Sum_{k>=0} x^(2^k).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 5, 10, 15, 25, 31, 30, 40, 50, 50, 60, 75, 65, 55, 70, 66, 70, 90, 100, 100, 90, 90, 100, 110, 100, 120, 120, 75, 65, 95, 70, 90, 110, 130, 100, 126, 110, 130, 140, 150, 140, 160, 120, 100, 90, 130, 100, 150, 140, 160, 120, 110, 100, 160, 120, 120, 120, 120
Offset: 0

Views

Author

N. J. A. Sloane, Jun 22 2009

Keywords

Comments

Number of ways to write n as an ordered sum of 5 powers of 2. - Ilya Gutkovskiy, Feb 02 2021

Crossrefs

(Sum_{k>=0} x^(2^k))^m; A209229 (m=1), A073267 (m=2), A151759 (m=3), A151760 (m=4), this sequence (m=5), A151762 (m=6).
Cf. A151758.

Programs

  • Maple
    b:= proc(n, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
          `if`(t<1, 0, add(b(n-2^j, t-1), j=0..ilog2(n))))
        end:
    a:= n-> b(n, 5):
    seq(a(n), n=0..62);  # Alois P. Heinz, Feb 02 2021
  • Mathematica
    b[n_, t_] := b[n, t] = If[n == 0, If[t == 0, 1, 0],
         If[t < 1, 0, Sum[b[n - 2^j, t - 1], {j, 0, Floor@Log2[n]}]]];
    a[n_] := b[n, 5];
    Table[a[n], {n, 0, 62}] (* Jean-François Alcover, Apr 25 2022, after Alois P. Heinz *)

A151762 G.f.: Theta^6, where Theta = Sum_{k>=0} x^(2^k).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 6, 15, 26, 45, 66, 76, 96, 126, 140, 165, 210, 221, 210, 240, 252, 246, 300, 346, 360, 366, 380, 396, 420, 440, 480, 525, 450, 405, 450, 416, 396, 510, 540, 510, 516, 582, 540, 636, 660, 720, 720, 706, 600, 630, 620, 636, 660, 800, 720, 756, 660, 720
Offset: 0

Views

Author

N. J. A. Sloane, Jun 22 2009

Keywords

Comments

Number of ways to write n as an ordered sum of 6 powers of 2. - Ilya Gutkovskiy, Feb 02 2021

Crossrefs

(Sum_{k>=0} x^(2^k))^m; A209229 (m=1), A073267 (m=2), A151759 (m=3), A151760 (m=4), A151761 (m=5), this sequence (m=6).
Cf. A151758.

Programs

  • Maple
    b:= proc(n, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
          `if`(t<1, 0, add(b(n-2^j, t-1), j=0..ilog2(n))))
        end:
    a:= n-> b(n, 6):
    seq(a(n), n=0..58);  # Alois P. Heinz, Feb 02 2021
  • Mathematica
    b[n_, t_] := b[n, t] = If[n == 0, If[t == 0, 1, 0],
         If[t < 1, 0, Sum[b[n - 2^j, t - 1], {j, 0, Floor@Log2[n]}]]];
    a[n_] := b[n, 6];
    Table[a[n], {n, 0, 58}] (* Jean-François Alcover, Apr 25 2022, after Alois P. Heinz *)

A151774 Characteristic function of numbers with binary weight 2 (A018900).

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Jun 23 2009

Keywords

Comments

a(A018900(n)) = 1; a(A161989(n)) = 0. - Reinhard Zumkeller, Jun 24 2009

Crossrefs

Programs

Formula

Let Theta = Sum_{k >= 0} x^(2^k). G.f. is (x + Theta^2 - Theta)/2 (cf. A151758).
Showing 1-5 of 5 results.