This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A165560 The arithmetic derivative of n, modulo 2. 4
 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Characteristic function of A235991: a(A235991(n))=1 and a(A235992(n))=0. - Reinhard Zumkeller, Mar 11 2014 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 FORMULA a(n)= A003415(n) mod 2. a(n)=(1-(-1)^n’)/2 MAPLE with(numtheory); P:=proc(i) local f, n, p, pfs; for n from 0 by 1 to i do   pfs:=ifactors(n)[2]; f:=n*add(op(2, p)/op(1, p), p=pfs);   print(1/2*(1-(-1)^f)); od; end: P(1000); MATHEMATICA d[0] = d[1] = 0; d[n_] := n*Total[f = FactorInteger[n]; f[[All, 2]]/f[[All, 1]] ]; a[n_] := Mod[d[n], 2]; Table[a[n], {n, 0, 104}] (* Jean-François Alcover, Apr 22 2015 *) PROG (Haskell) a165560 = flip mod 2 . a003415  -- Reinhard Zumkeller, Mar 11 2014 CROSSREFS Sequence in context: A286807 A126564 A180433 * A014306 A138150 A271591 Adjacent sequences:  A165557 A165558 A165559 * A165561 A165562 A165563 KEYWORD easy,nonn AUTHOR Paolo P. Lava & Giorgio Balzarotti, Sep 24 2009 EXTENSIONS Entries checked by R. J. Mathar, Oct 07 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 6 06:34 EST 2019. Contains 329784 sequences. (Running on oeis4.)