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.

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A013675 Decimal expansion of zeta(17).

Original entry on oeis.org

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

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Author

Keywords

Examples

			1.0000076371976378997622736002935630292130882490902626790953798439729356...
		

Crossrefs

Programs

Formula

From Peter Bala, Dec 04 2013: (Start)
Definition: zeta(17) = sum {n >= 1} 1/n^17.
zeta(17) = 2^17/(2^17 - 1)*( sum {n even} n^11*p(n)*p(1/n)/(n^2 - 1)^18 ), where p(n) = n^8 + 36*n^6 + 126*n^4 + 84*n^2 + 9. Cf. A013663, A013667 and A013671.
(End)
zeta(17) = Sum_{n >= 1} (A010052(n)/n^(17/2)) = Sum_{n >= 1} ( (floor(sqrt(n)) - floor(sqrt(n-1)))/n^(17/2) ). - Mikael Aaltonen, Feb 23 2015
zeta(17) = Product_{k>=1} 1/(1 - 1/prime(k)^17). - Vaclav Kotesovec, May 02 2020

A051343 Number of ways of writing n as a sum of 3 nonnegative cubes (counted naively).

Original entry on oeis.org

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

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Author

Keywords

Crossrefs

Cf. A051344.
Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

Programs

  • Maple
    series(add(x^(n^3), n=0..10)^3,x,1000);
  • PARI
    first(n)=my(s=vector(n+1)); for(k=0,sqrtnint(n,3), s[k^3+1]=1); Vec(Ser(s,,n+1)^3) \\ Charles R Greathouse IV, Sep 16 2016

A113061 Sum of cube divisors of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 28, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 28, 1, 9, 1, 1, 1, 1, 1, 1, 1, 73, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9, 28, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 9
Offset: 1

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Author

Paul Barry, Oct 13 2005

Keywords

Comments

Multiplicative with a(p^e) = (p^(3*(1+floor(e/3)))-1)/(p^3-1). The Dirichlet generating function is zeta(s)*zeta(3s-3). The sequence is the inverse Mobius transform of n*A010057(n). - R. J. Mathar, Feb 18 2011

Crossrefs

Programs

  • Maple
    A113061 := proc(n)
        local a,pe,p,e;
        a := 1;
        for pe in ifactors(n)[2] do
            p := pe[1] ;
            e := pe[2] ;
            e := 3*(1+floor(e/3)) ;
            a := a*(p^e-1)/(p^3-1) ;
        end do:
        a ;
    end proc:
    seq(A113061(n),n=1..100) ; # R. J. Mathar, Oct 08 2017
  • Mathematica
    a[n_] := Sum[If[IntegerQ[d^(1/3)], d, 0], {d, Divisors[n]}];
    Array[a, 100] (* Jean-François Alcover, Nov 25 2017 *)
    f[p_, e_] := (p^(3*(1 + Floor[e/3])) - 1)/(p^3 - 1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, May 01 2020 *)
  • PARI
    A113061(n) = sumdiv(n,d,ispower(d,3)*d); \\ Antti Karttunen, Oct 08 2017
    
  • Scheme
    ;; With memoization-macro definec, after the multiplicative formula of R. J. Mathar:
    (definec (A113061 n) (if (= 1 n) n (let ((p (A020639 n)) (e (A067029 n))) (* (/ (+ -1 (expt p (* 3 (+ 1 (A002264 e))))) (+ -1 (expt p 3))) (A113061 (A028234 n)))))) ;; Antti Karttunen, Oct 08 2017

Formula

G.f.: Sum_{k>=1} k^3*x^(k^3)/(1 - x^(k^3)). - Ilya Gutkovskiy, Dec 24 2016
a(n) = Sum_{d|n} A010057(d)*d. - Antti Karttunen, Oct 08 2017
Sum_{k=1..n} a(k) ~ zeta(4/3)*n^(4/3)/4 - n/2. - Vaclav Kotesovec, Dec 01 2020

A173677 Number of ways of writing n as a sum of two nonnegative cubes.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Nov 24 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^2.

Crossrefs

Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

Programs

Formula

a(n) = Sum_{k=0..n} c(k) * c(n-k), where c = A010057. - Wesley Ivan Hurt, Nov 09 2023

A173682 Number of ways of writing n as a sum of 9 nonnegative cubes.

Original entry on oeis.org

1, 9, 36, 84, 126, 126, 84, 36, 18, 73, 252, 504, 630, 504, 252, 72, 45, 252, 756, 1260, 1260, 756, 252, 36, 84, 504, 1260, 1689, 1332, 756, 588, 630, 630, 882, 1332, 1341, 1134, 1638, 2520, 2520, 1638, 1008, 828, 756, 1638, 3780, 5040, 3780, 1596, 504, 252, 588, 2520, 5040, 5076, 2772, 1296, 1332, 1296, 1386, 2772, 3816, 2772, 2142, 3798, 5121, 4032
Offset: 0

Views

Author

N. J. A. Sloane, Nov 25 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^9.

Crossrefs

Cf. A173677.
Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

A173676 Number of ways of writing n as a sum of seven nonnegative cubes.

Original entry on oeis.org

1, 7, 21, 35, 35, 21, 7, 1, 7, 42, 105, 140, 105, 42, 7, 0, 21, 105, 210, 210, 105, 21, 0, 0, 35, 140, 210, 147, 77, 105, 140, 105, 77, 112, 105, 77, 210, 420, 420, 210, 63, 42, 21, 105, 420, 630, 420, 105, 7, 7, 0, 140, 420, 420, 161, 105, 211, 210, 105, 126, 210, 105, 105, 420, 637, 462, 210, 182, 147, 42, 217, 630, 672, 420, 420, 427, 210, 42
Offset: 0

Views

Author

N. J. A. Sloane, Nov 24 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^7.
It is known that a(n)>0 if n is even and > 454.

Crossrefs

Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

A173678 Number of ways of writing n as a sum of 4 nonnegative cubes.

Original entry on oeis.org

1, 4, 6, 4, 1, 0, 0, 0, 4, 12, 12, 4, 0, 0, 0, 0, 6, 12, 6, 0, 0, 0, 0, 0, 4, 4, 0, 4, 12, 12, 4, 0, 1, 0, 0, 12, 24, 12, 0, 0, 0, 0, 0, 12, 12, 0, 0, 0, 0, 0, 0, 4, 0, 0, 6, 12, 6, 0, 0, 0, 0, 0, 12, 12, 4, 12, 12, 4, 0, 0, 6, 0, 12, 24, 12, 0, 0, 0, 0, 0, 12, 16, 4, 0, 0, 0, 0, 0, 4, 4, 0, 12, 24, 12, 0, 0, 0, 0, 0, 24, 24, 0, 0, 0, 0, 0, 0, 12, 1, 0, 0
Offset: 0

Views

Author

N. J. A. Sloane, Nov 24 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^4.

Crossrefs

Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.
Without order you get A025448.

A173679 Number of ways of writing n as a sum of 5 nonnegative cubes.

Original entry on oeis.org

1, 5, 10, 10, 5, 1, 0, 0, 5, 20, 30, 20, 5, 0, 0, 0, 10, 30, 30, 10, 0, 0, 0, 0, 10, 20, 10, 5, 20, 30, 20, 5, 5, 5, 0, 20, 60, 60, 20, 0, 1, 0, 0, 30, 60, 30, 0, 0, 0, 0, 0, 20, 20, 0, 10, 30, 30, 10, 0, 5, 0, 0, 30, 60, 35, 20, 30, 20, 5, 0, 30, 30, 20, 60, 60, 20, 0, 0, 10, 0, 30, 70, 50, 10, 0, 0, 0, 0, 20, 40, 20, 20, 60, 60, 20, 0, 5, 10, 0, 60, 120
Offset: 0

Views

Author

N. J. A. Sloane, Nov 25 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^5.

Crossrefs

Cf. A173677.
Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

A173680 Number of ways of writing n as a sum of 6 nonnegative cubes.

Original entry on oeis.org

1, 6, 15, 20, 15, 6, 1, 0, 6, 30, 60, 60, 30, 6, 0, 0, 15, 60, 90, 60, 15, 0, 0, 0, 20, 60, 60, 26, 30, 60, 60, 30, 21, 30, 15, 30, 120, 180, 120, 30, 6, 6, 0, 60, 180, 180, 60, 0, 1, 0, 0, 60, 120, 60, 15, 60, 90, 60, 15, 30, 30, 0, 60, 180, 186, 90, 60, 66, 30, 6, 90, 180, 120, 120, 180, 120, 30, 0, 60, 60, 60, 200, 240, 120, 20, 0, 15, 0, 60, 180, 180
Offset: 0

Views

Author

N. J. A. Sloane, Nov 25 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^6.

Crossrefs

Cf. A173677.
Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

A173681 Number of ways of writing n as a sum of 8 nonnegative cubes.

Original entry on oeis.org

1, 8, 28, 56, 70, 56, 28, 8, 9, 56, 168, 280, 280, 168, 56, 8, 28, 168, 420, 560, 420, 168, 28, 0, 56, 280, 560, 568, 336, 224, 280, 280, 238, 336, 428, 336, 406, 840, 1120, 840, 392, 224, 168, 224, 840, 1680, 1680, 840, 196, 56, 28, 280, 1120, 1680, 1148, 448, 428, 568, 420, 448, 868, 840, 448, 840, 1689, 1736, 1008, 616, 616, 336, 476, 1688, 2576
Offset: 0

Views

Author

N. J. A. Sloane, Nov 25 2010

Keywords

Comments

Order matters. This is the coefficient of q^n in the expansion of {Sum_{m>=0} q^(m^3)}^8.

Crossrefs

Sums of k cubes, number of ways of writing n as, for k=1..9: A010057, A173677, A051343, A173678, A173679, A173680, A173676, A173681, A173682.

Programs

  • PARI
    lista(n)=my(q='q); Vec(sum(m=0, (n+.5)^(1/3), q^(m^3), O(q^(n+1)))^8); \\ Michel Marcus, Apr 12 2016
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