id:A068346 - OEIS Search Results

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a(n) = n'' = second arithmetic derivative of n.

+0
3

0, 0, 0, 4, 0, 1, 0, 16, 5, 1, 0, 32, 0, 6, 12, 80, 0, 10, 0, 44, 7, 1, 0, 48, 7, 8, 27, 80, 0, 1, 0, 176, 9, 1, 16, 92, 0, 10, 32, 72, 0, 1, 0, 112, 16, 10, 0, 240, 9, 39, 24, 92, 0, 108, 32, 96, 13, 1, 0, 96, 0, 14, 20, 640, 21, 1, 0, 156, 15, 1, 0, 220, 0, 16, 16, 176, 21, 1, 0, 368, 216 (list; graph; listen)

	OFFSET	`1,4`
	LINKS	`T. D. Noe, Table of n, a(n) for n=1..2000`
	FORMULA	`a(n) = A003415(A003415(n)).`
	MATHEMATICA	`dn[0]=0; dn[1]=0; dn[n_]:=Module[{f=Transpose[FactorInteger[n]]}, If[PrimeQ[n], 1, Plus@@(n*f[[2]]/f[[1]])]]; Table[dn[dn[n]], {n, 100}] (T. D. Noe)`
	CROSSREFS	`Cf. A003415 (arithmetic derivative of n), A099306 (third arithmetic derivative of n).` `Sequence in context: A046781 A117435 A117436 this_sequence A006838 A061309 A059064` `Adjacent sequences: A068343 A068344 A068345 this_sequence A068347 A068348 A068349`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 28 2002`
	EXTENSIONS	`More terms from T. D. Noe (noe(AT)sspectra.com), Oct 12 2004`

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Last modified September 6 16:04 EDT 2008. Contains 143483 sequences.

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