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.

A000175 Related to zeros of Bessel function.

Original entry on oeis.org

1, 1, 2, 11, 38, 946, 4580, 202738, 3786092, 261868876, 1992367192, 2381255244240, 21411255538848, 2902625722978656, 451716954504285504, 319933105641374465472, 3761845343198709705600
Offset: 1

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Comments

Constant term of the Rayleigh polynomials. [From Herman Jamke (hermanjamke(AT)fastmail.fm), Aug 20 2010]

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Programs

  • Mathematica
    pi0[n_] := Product[k^Floor[n/k], {k, 1, n}]; J[v_, m_] := Sum[(-1)^n*(x/2)^( 2*n + v)/(n!*(n+v)!), {n, 0, m}] + O[x]^(2*m+v); p = J[1, 101]/(2*J[0, 101]); Reap[For[n=1, n <= 40, n += 2, Print["a(", (n+1)/2, ") = ", an = SeriesCoefficient[p, n]*pi0[(n+1)/2]*2^(n+1)]; Sow[an]]][[2, 1]] (* Jean-François Alcover, Feb 04 2016, adapted from Herman Jamke's 2nd PARI script *)
  • PARI
    alpha(k,n)=if(k
    				
  • PARI
    pi0(n)=prod(k=1,n,k^floor(n/k))
    J(v,m)=sum(n=0,m,(-1)^n*(x/2)^(2*n+v)/(n!*(n+v)!))+O(x^(2*m+v))
    p=J(1,101)/(2*J(0,101));forstep(n=1,200,2,print((n+1)/2" "polcoeff(p,n)*pi0((n+1)/2)*2^(n+1))) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 03 2010

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Aug 20 2010