A238324 a(1) = 1 and a(n+1) = if a(n) > 2*n+1 then a(n)-2*n-1 else a(n)+2*n+1.

1, 4, 9, 2, 11, 22, 9, 24, 7, 26, 5, 28, 3, 30, 1, 32, 65, 30, 67, 28, 69, 26, 71, 24, 73, 22, 75, 20, 77, 18, 79, 16, 81, 14, 83, 12, 85, 10, 87, 8, 89, 6, 91, 4, 93, 2, 95, 190, 93, 192, 91, 194, 89, 196, 87, 198, 85, 200, 83, 202, 81, 204, 79, 206, 77

Offset: 1

Author

Reinhard Zumkeller, Dec 07 2015

Keywords

• nonn

Comments

Abs(a(n+1) - a(n)) = 2*n+1;

a(A265327(n)) = n and a(m) != n for m < A265327(n).

Links

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

Crossrefs

Cf. A005408, A046901, A265327.

Programs

Haskell

a238324 n = a238324_list !! (n-1)
a238324_list = scanl1 (\u v -> if u > v then u - v else u + v) [1, 3 ..]

Mathematica

nxt[{n_,a_}]:={n+1,If[a>2n+1,a-2n-1,a+2n+1]}; NestList[nxt,{1,1},70][[All,2]] (* Harvey P. Dale, Oct 07 2016 *)