The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A104997 Denominators of coefficients in a series solution to a certain ODE. 4
 1, 8, 128, 15360, 3440640, 247726080, 653996851200, 476109707673600, 457065319366656000, 43034457761906688000, 850360885375276154880000, 1571466916173510334218240000, 693959790182222163590774784000, 9021477272368888126680072192000000, 27280947271643517695080538308608000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Series solution of ode (A.Gruzinov,2005): cos[t]f'[t]+sin[t]f''[t]+3/4 sin[t]f[t]=0, f[-Pi/2]=1, f'[-Pi/2]=0, f[t]=1-3/8(t+Pi/2)^2-5/128(t+Pi/2)^4-193/15360(t+Pi/2)^4-... All coefficients (except 1) are negative, there is no simple recursion or other formula for the series coefficients. REFERENCES A. Gruzinov, Power of axisymmetric pulsar, Phys. Rev. Lett. 94 (021101)(2005). LINKS Robert Israel, Table of n, a(n) for n = 1..203 A. Gruzinov, Power of axisymmetric pulsar, arXiv:astro-ph/0407279, 2004. FORMULA The solution to the ode is hypergeom([-1/4,3/4],[1/2],sin(t+Pi/2)). - Robert Israel, Jun 05 2019 MAPLE de:= sin(s)*D(g)(s)-cos(s)*(D@@2)(g)(s)-3/4*cos(s)*g(s)=0: S:= dsolve({de, g(0)=1, D(g)(0)=0}, g(s), series, order=51): seq(denom(coeff(rhs(S), s, 2*j)), j=0..25); # Robert Israel, Jun 05 2019 CROSSREFS Cf. A104996 (numerators). Sequence in context: A113135 A219264 A188060 * A265097 A027951 A041115 Adjacent sequences:  A104994 A104995 A104996 * A104998 A104999 A105000 KEYWORD nonn,frac AUTHOR Zak Seidov, Mar 31 2005 EXTENSIONS More terms from Robert Israel, Jun 05 2019 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 22 19:03 EDT 2020. Contains 337953 sequences. (Running on oeis4.)