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.

A063226 Dimension of the space of weight 2n cuspidal newforms for Gamma_0(63).

Original entry on oeis.org

3, 7, 13, 17, 23, 27, 33, 37, 43, 47, 53, 57, 63, 67, 73, 77, 83, 87, 93, 97, 103, 107, 113, 117, 123, 127, 133, 137, 143, 147, 153, 157, 163, 167, 173, 177, 183, 187, 193, 197, 203, 207, 213, 217, 223, 227, 233, 237, 243, 247
Offset: 1

Views

Author

N. J. A. Sloane, Jul 10 2001

Keywords

Comments

Also, dimension of the space of weight 2n cuspidal newforms for Gamma_0(88). - N. J. A. Sloane, Nov 24 2016
First differences are 4,6,4,6,4,6.... Also values of k such that k^(10*n) mod 10 = 8*(n mod 2)+1. - Gary Detlefs, Jul 04 2014
In other words, numbers n such that n^(2+4*k) + 1 is divisible by 10, for k >= 0. - Altug Alkan, Mar 30 2016
The rational generating function, the periodic first differences and Greubel's closed form are an immediate consequence of the structure of formula given by [Martin]. - R. J. Mathar, Apr 09 2016
A quasipolynomial of order 2 and degree 1: a(n) = 5n - 3 if n is even and 5n - 2 if n is odd. - Charles R Greathouse IV, Nov 03 2021
Numbers that are congruent to {3, 7} mod 10. - Amiram Eldar, Nov 23 2024

Crossrefs

Cf. A017305 (bisection), A017353 (bisection), A019934, A182007.

Programs

  • Maple
    # see A063195
  • Mathematica
    Table[4 Floor[n/2] + 6 Floor[(n - 1)/2] + 3, {n, 50}] (* or *)
    Table[SeriesCoefficient[3 x - x^2 (-7 - 6 x + 3 x^2)/((1 + x) (x - 1)^2), {x, 0, n}], {n, 50}] (* Michael De Vlieger, Mar 30 2016 *)
    LinearRecurrence[{1, 1, -1}, {3, 7, 13}, 100] (* G. C. Greubel, Mar 30 2016 *)
  • PARI
    my(x='x+O('x^99)); Vec(3*x-x^2*(-7-6*x+3*x^2)/((1+x)*(x-1)^2)) \\ Altug Alkan, Mar 31 2016
    
  • PARI
    a(n)=5*n-3+n%2 \\ Charles R Greathouse IV, Mar 31 2016

Formula

a(n) = 4*floor(n/2) + 6*floor((n-1)/2) + 3. - Gary Detlefs, Jul 04 2014
G.f.: 3*x - x^2*(-7-6*x+3*x^2)/((1+x)*(x-1)^2). - R. J. Mathar, Jul 15 2015
From G. C. Greubel, Mar 30 2016: (Start)
a(n) = (1/2)*(10*n - 5 - (-1)^n).
E.g.f.: (5*x + 3)*cosh(x) + (5*x + 2)*sinh(x). (End)
Sum_{n>=1} (-1)^(n+1)/a(n) = sqrt(5-2*sqrt(5))*Pi/10. - Amiram Eldar, Sep 26 2022
From Amiram Eldar, Nov 23 2024: (Start)
Product_{n>=1} (1 - (-1)^n/a(n)) = 2*sin(Pi/5) (A182007).
Product_{n>=1} (1 + (-1)^n/a(n)) = tan(Pi/5) (A019934). (End)

A127788 Dimension of the space of newforms of weight 2 and level n.

Original entry on oeis.org

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

Views

Author

Steven Finch, Apr 04 2007

Keywords

Comments

"Newform" is meant in the sense of Atkin-Lehner, that is, a primitive Hecke eigenform relative to the subgroup Gamma_0(n).

Examples

			a(p) = A001617(p) for any prime p.
G.f. = x^11 + x^14 + x^15 + x^17 + x^19 + x^20 + x^21 + 2*x^23 + x^24 + ...
		

References

  • H. Cohen, Number Theory. Vol. II. Analytic and Modern Tools. Springer, 2007, pp. 496-497.
  • Toshitsune Miyake, Modular Forms, Springer-Verlag, 1989. See Table A.

Crossrefs

Programs

  • Maple
    seq( g0star(2,N),N=1..80); # using the source in A063195 - R. J. Mathar, Jul 15 2015
  • Mathematica
    A001617[n_] := If[n < 1, 0, 1 + Sum[MoebiusMu[d]^2 n/d/12 - EulerPhi[GCD[d, n/d]]/2, {d, Divisors@n}] - Count[(#^2 - # + 1)/n & /@ Range[n], ?IntegerQ]/3 - Count[(#^2 + 1)/n & /@ Range[n], ?IntegerQ]/4]; a[n_ /; n < 10] = 0; a[n_] := a[n] =  A001617[n] - Sum[a[m]*DivisorSigma[0, n/m], {m, Divisors[n][[2 ;; -2]]}]; Table[a[n], {n, 1, 102}] (* Jean-François Alcover, Sep 07 2015, A001617 code due to Michael Somos *)
  • PARI
    {a(n) = my(v = [1, 3, 4, 6], A, p, e); if( n<1, 0, A = factor(n); for( k=1, matsize(A)[1], [p, e] = A[k,]; v[1] *= if( e==1, p-1, e==2, p^2-p-1, p^(e-3) * (p+1) * (p-1)^2); v[2] *= if( p==2, (e==3) - (e<3), e==1, kronecker(-4, p) - 1, e==2, -kronecker(-4, p)); v[3] *= if( p==3, (e==3) - (e<3), e==1, kronecker(-3, p) - 1, e==2, -kronecker(-3, p)); v[4] *= if( e%2, 0, e==2, p-2, p^(e/2-2) * (p-1)^2)); moebius(n) + (v[1] - v[2] - v[3] - v[4]) / 12 )}; /* Michael Somos, Jun 06 2015 */

Formula

a(n) = A001617(n) - sum a(m)*d(n/m), where the summation is over all divisors 1 < m < n of n and d is the divisor function.

A063279 Dimension of the space of weight n cuspidal newforms for Gamma_1( 6 ).

Original entry on oeis.org

-1, 0, 0, 1, 2, 1, 2, 1, 2, 1, 4, 3, 4, 1, 4, 3, 6, 3, 6, 3, 6, 3, 8, 5, 8, 3, 8, 5, 10, 5, 10, 5, 10, 5, 12, 7, 12, 5, 12, 7, 14, 7, 14, 7, 14, 7, 16, 9, 16, 7, 16, 9, 18, 9, 18, 9, 18, 9, 20, 11, 20, 9, 20, 11, 22, 11, 22, 11, 22, 11, 24, 13, 24, 11, 24, 13, 26, 13
Offset: 2

Views

Author

N. J. A. Sloane, Jul 14 2001

Keywords

Crossrefs

Cf. A302402 (bisection), A063195 (bisection)

Formula

g.f.: x^2*(x^9-2*x^8+2*x^6-2*x^5+3*x^4+x-1) / ((x-1)^2*(x+1)^2*(x^2-x+1)*(x^2+1)). - Colin Barker, Feb 24 2015

A260088 Dimension of the space of newforms of weight 4 and level n.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 1, 3, 2, 2, 1, 4, 1, 4, 1, 4, 3, 5, 1, 3, 3, 4, 2, 7, 2, 7, 3, 6, 4, 6, 1, 9, 5, 6, 3, 10, 2, 10, 3, 5, 6, 11, 3, 8, 5, 8, 3, 13, 4, 10, 4, 10, 7, 14, 2, 15, 8, 7, 5, 12, 4, 16, 4, 12, 6, 17, 4, 18, 9, 10, 5, 16, 6, 19, 6
Offset: 1

Views

Author

R. J. Mathar, Jul 15 2015

Keywords

Crossrefs

Programs

  • Maple
    seq(g0star(4,N),N=1..80); # using functions coded in A063195
Showing 1-4 of 4 results.