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A090636
Trajectory of 15 under the map k -> A003415(k) (taking the arithmetic derivative).
6
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
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
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 14 2003
EXTENSIONS
More explicit name from M. F. Hasler, Nov 27 2019
STATUS
approved