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

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A228474 This is a Recamán-like sequence (cf. A005132). Starting at n, a(n) is the number of steps required to reach zero. On the k-th step move a distance of k in the direction of zero. If the number landed on has been landed on before, move a distance of k away from zero instead. 9
0, 1, 4, 2, 24, 26, 3, 1725, 12, 14, 4, 26, 123, 125, 15, 5, 119, 781802, 20, 22, 132896, 6, 51, 29, 31, 1220793, 23, 25, 7, 429, 8869123, 532009, 532007, 532009, 532011, 26, 8, 94, 213355, 213353, 248, 33, 31, 33, 1000, 9, 144, 110, 112, 82, 84, 210, 60, 34 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The n-th triangular number T_n has a(T_n) = n.

a(n) + 1 = length of row n in tables A248939 and A248973. - Reinhard Zumkeller, Oct 20 2014

LINKS

Jon E. Schoenfield, Table of n, a(n) for n = 0..10000

Gordon Hamilton, Wrecker Ball Sequences, Video, 2013

Index entries for sequences related to Recamán's sequence

EXAMPLE

a(2) = 4 because 2 -> 1 -> -1 -> -4 -> 0.

PROG

(PARI) a(n)=my(v=List([n]), k, t, t2, steps); while(n, steps++; k++; if(n>0, t=n-k; t2=n+k, t=n+k; t2=n-k); for(i=1, #v, if(v[i]==t, listput(v, n=t2); next(2))); listput(v, n=t)); steps \\ Charles R Greathouse IV, Aug 18 2014

(Haskell)

a228474 = subtract 1 . length . a248939_row  -- Reinhard Zumkeller, Oct 20 2014

CROSSREFS

Cf. A005132.

Cf. A248939, A248973.

Sequence in context: A241437 A030211 A134461 * A058167 A140331 A095896

Adjacent sequences:  A228471 A228472 A228473 * A228475 A228476 A228477

KEYWORD

walk,nonn

AUTHOR

Gordon Hamilton, Aug 23 2013

EXTENSIONS

More terms from Jon E. Schoenfield, Jan 10 2014

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified May 26 16:52 EDT 2017. Contains 287130 sequences.