The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A072818 Possibly the only integers of the form sqrt(m^2*(m^2-1)*2/3) [only checked for the first 5 terms]. 2
 0, 20, 1960, 192060, 18819920, 1844160100, 180708869880, 17707625088140, 1735166549767840, 170028614252160180, 16661069030161929800, 1632614736341616960220, 159979583092448300171760 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS These are the standard deviations of time for a random walk starting at 0 to reach one of the boundaries at +A001079(n) or -A001079(n) for the first time. LINKS Indranil Ghosh, Table of n, a(n) for n = 0..501 Tanya Khovanova, Recursive Sequences Index entries for linear recurrences with constant coefficients, signature (98, -1). FORMULA a(n) = 98*a(n-1)-a(n-2) [starting with a(0)=0 and a(1)=20] =sqrt(A072819(A001079(n))). G.f.: 20x/(1-98x+x^2). [Philippe Deléham, Nov 18 2008] EXAMPLE 0 and 20 are at the start of the sequence since m^2*(m^2-1)*2/3 (A072819) starts 0, 0, 8, 48, 160, 400, 840, 1568, ... and the only squares among these are 0 and 400 with square roots of 0 and 20. CROSSREFS Sequence in context: A246619 A222973 A267575 * A123479 A071152 A195622 Adjacent sequences: A072815 A072816 A072817 * A072819 A072820 A072821 KEYWORD nonn AUTHOR Henry Bottomley, Jul 14 2002 STATUS approved

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

Last modified August 7 22:54 EDT 2024. Contains 375018 sequences. (Running on oeis4.)