login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A038533 Denominator of coefficients of both EllipticK/Pi and EllipticE/Pi. 17
2, 8, 128, 512, 32768, 131072, 2097152, 8388608, 2147483648, 8589934592, 137438953472, 549755813888, 35184372088832, 140737488355328, 2251799813685248, 9007199254740992, 9223372036854775808 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Denominators are powers of 2 since EllipticK[x]=Pi Sum[2^(-1-4n) Binomial[2n,n]^2 x^n,{ n,0,\[Infinity]}] and EllipticE[x]=Pi Sum[2^(-1-4n)(-1)^(2n) Binomial[2n,n]^2 /(-2n+1) x^n,{n,0,\[ Infinity]}]

LINKS

Table of n, a(n) for n=0..16.

Index to divisibility sequences

FORMULA

a(n) = 2^(1+4n- 2 w[n]) with w[n] = A000120 = number of 1's in binary expansion of n

PROG

(PARI) a(n)=my(s=n); while(n>>=1, s+=n); 2<<(2*s) \\ Charles R Greathouse IV, Apr 07 2012

CROSSREFS

Cf. A038534, A038535.

Equals 2*A056982(n).

Sequence in context: A156497 A064205 A081856 * A139290 A152922 A114977

Adjacent sequences:  A038530 A038531 A038532 * A038534 A038535 A038536

KEYWORD

nonn,frac

AUTHOR

Wouter Meeussen, revised Jan 03 2001

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 21 22:16 EST 2019. Contains 329383 sequences. (Running on oeis4.)