A232244 A walk based on the digits of sqrt(2) (A002193).

1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 8, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 8, 7, 6, 5, 4, 3, 2, 3, 4, 3

Offset

1,2

Comments

sqrt(2)= 1. 41421354237...

Between 1 and 4 we place 2 and 3.

Between 4 and 1 we place 3 and 2.

Between 1 and 4 we place 2 and 3.

Between 4 and 2 we place 3 and so on.

This gives:

1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, ...

This could be called a walk (or promenade) on the digits of sqrt(2).

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Prog

(Haskell)
a232244 n = a232244_list !! (n-1)
a232244_list = 1 : concat (zipWith w a002193_list $ tail a002193_list)
   where w v u | v > u     = [v - 1, v - 2 .. u]
               | v < u     = [v + 1 .. u]
               | otherwise = [v]
-- Reinhard Zumkeller, Nov 22 2013

Crossrefs

Cf. A002193.

Sequence in context: A017859 A171456 A028356 * A260644 A073791 A350862

Adjacent sequences: A232241 A232242 A232243 * A232245 A232246 A232247

Keyword

nonn,easy,base

Author

Philippe Deléham, Nov 20 2013 at the suggestion of N. J. A. Sloane

Status

approved