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 1-4 of 4 results.

A305757 Inverse Euler transform of q*(j-720) where j is j-function (A000521).

Original entry on oeis.org

24, 196584, 16773144, -18919981056, -3292295086056, 2312547886368744, 640457437563740184, -302667453389051314176, -123005476312830648176616, 39529719620247267255853032, 23306082528463942764630528024, -4849033309391159571741461446656
Offset: 1

Views

Author

Seiichi Manyama, Jun 10 2018

Keywords

Comments

(Conjecture) Let {b_n} = inverse Euler transform of (q*(j+144*k)). b_n is a multiple of 24.

Examples

			(1-x)^(-24) * (1-x^2)^(-196584) * (1-x^3)^(-16773144) * (1-x^4)^18919981056 * ... = 1 + 24*x + 196884*x^2 + 21493760*x^3 + 864299970*x^4 + ... .
		

Crossrefs

Inverse Euler transform of q*(j+144*k): (-1)*A192731 (k=0), this sequence (k=-5), (-1)*A289061 (k=-12).
Cf. A000521, A007240 (j-720), A302407, A305756.

Formula

q*(j-720) = Product_{k>0} (1 - x^k)^(-a(k)).

A305758 Coefficients of (q*(j(q)-720))^(-1/24) where j(q) is the elliptic modular invariant.

Original entry on oeis.org

1, -1, -8191, -690690, 822573570, 142081621501, -102803639194620, -28281091311058949, 13668272700177314310, 5514776417237892113400, -1808663163639294990384630, -1056880191873167904305607180, 224746784451252089897697350159
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2018

Keywords

Crossrefs

(q*(j(q)-720))^(m/24): A305760 (m=-24), this sequence (m=-1), A305756 (m=1).
Cf. A000521, A007240 (j(q)-720), A305757.

Formula

Convolution inverse of A305756.

A305760 Coefficients of 1/(q*(j(q)-720)) where j(q) is the elliptic modular invariant.

Original entry on oeis.org

1, -24, -196308, -12057152, 38590826190, 5667574866912, -7304962792606024, -1755598494902269440, 1325502689549152990437, 465173370338426065214640, -228213884020015849568089308, -112934890287321570650976240384
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2018

Keywords

Crossrefs

(q*(j(q)-720))^(m/24): this sequence (m=-24), A305758 (m=-1), A305756 (m=1).
Cf. A000521, A007240 (j(q)-720), A305699, A305757.

Formula

G.f.: Product_{k>0} (1 - x^k)^A305757(k).

A305762 a(0) = 24, a(n) = 2^(max(0, min(3, p - 1))) * 3^(max(0, min(1, q - 1))) where n = 2^p * 3^q * 5^r * ... .

Original entry on oeis.org

24, 1, 1, 1, 2, 1, 1, 1, 4, 3, 1, 1, 2, 1, 1, 1, 8, 1, 3, 1, 2, 1, 1, 1, 4, 1, 1, 3, 2, 1, 1, 1, 8, 1, 1, 1, 6, 1, 1, 1, 4, 1, 1, 1, 2, 3, 1, 1, 8, 1, 1, 1, 2, 1, 3, 1, 4, 1, 1, 1, 2, 1, 1, 3, 8, 1, 1, 1, 2, 1, 1, 1, 12, 1, 1, 1, 2, 1, 1, 1, 8, 3, 1, 1, 2, 1, 1, 1, 4, 1
Offset: 0

Views

Author

Seiichi Manyama, Jun 10 2018

Keywords

Crossrefs

Cf. A305756.

Programs

  • Mathematica
    a[n_] := GCD[24, n/GCD[6, n]]; Array[a, 100, 0] (* Amiram Eldar, Oct 15 2022 *)
  • PARI
    a(n)=gcd(24, n/gcd(6,n)) \\ Andrew Howroyd, Jul 24 2018
    
  • Ruby
    require 'prime'
    def A305762(n)
      return 24 if n == 0
      s = 1
      s *= 3 if n % 9 == 0
      n.prime_division.each{|i|
        s *= 2 ** [3, (i[1] - 1)].min if i[0] == 2
      }
      s
    end
    p (0..144).map{|i| A305762(i)}

Formula

a(n+144) = a(n).
a(n) = gcd(24, n/gcd(6,n)). - Andrew Howroyd, Jul 24 2018
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 77/36. - Amiram Eldar, Oct 15 2022

Extensions

Keyword:mult added by Andrew Howroyd, Jul 24 2018
Showing 1-4 of 4 results.