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!)
 A130036 Denominators of partial sums of a series for the inverse of the arithmetic-geometric mean (agM) of 1 and sqrt(3)/2. 3
 1, 16, 1024, 16384, 4194304, 67108864, 4294967296, 68719476736, 70368744177664, 1125899906842624, 72057594037927936, 1152921504606846976, 295147905179352825856, 4722366482869645213696, 302231454903657293676544 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS See the references and the W. Lang link under A130035. Also denominators of partial sums of a series for the inverse of the arithmetic-geometric mean (agM) of 1 and 1/2. For the numerators and the formula see A130037. Proof of the coincidence: The prefactor of each term of the sum (first formula in A130037) is binomial(2*n,n)^2, a natural number and 3 will never divide the even denominators. LINKS FORMULA a(n) = denom(sum((((2*j)!/(j!^2))^2)*(1/2^(6*j)),j=0..n)), n>=0. CROSSREFS Sequence in context: A159683 A197104 A067490 * A013735 A180376 A162008 Adjacent sequences:  A130033 A130034 A130035 * A130037 A130038 A130039 KEYWORD nonn,frac,easy AUTHOR Wolfdieter Lang Jun 01 2007 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 July 28 19:33 EDT 2021. Contains 346335 sequences. (Running on oeis4.)