A090636 Trajectory of 15 under the map k -> A003415(k) (taking the arithmetic derivative).

15, 8, 12, 16, 32, 80, 176, 368, 752, 1520, 3424, 8592, 20096, 70464, 235072, 705280, 3023616, 13223680, 55540736, 278539264, 1392697344, 9541095424, 58609614848, 410267320320, 3397142953984, 24143851798528, 176071227916288, 1232666139967488

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Formula

a(n) = A129150(n-2) for n>1. - Reinhard Zumkeller, Apr 01 2007

Prog

(Haskell)
a090636 n = a090636_list !! (n-1)
a090636_list = iterate a003415 15  -- Reinhard Zumkeller, Apr 29 2012
(PARI) A090636(n, a=15)={if(n<0, vector(-n, n, if(n>1, a=A003415(a), a)), for(n=2, n, a=A003415(a)); a)}  \\ For n<0 return the vector a[1..-n]. - M. F. Hasler, Nov 27 2019

Crossrefs

Sequence in context: A194707 A094501 A320572 * A126892 A195035 A245624

Adjacent sequences: A090633 A090634 A090635 * A090637 A090638 A090639

Keyword

nonn

Author

N. J. A. Sloane, Dec 14 2003

Extensions

More explicit name from M. F. Hasler, Nov 27 2019

Status

approved