The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A025479 Largest exponents of perfect powers (A001597). 15
 2, 2, 3, 2, 4, 2, 3, 5, 2, 2, 6, 4, 2, 2, 3, 7, 2, 2, 2, 3, 2, 5, 8, 2, 2, 3, 2, 2, 2, 2, 9, 2, 2, 4, 2, 6, 2, 2, 2, 2, 3, 10, 2, 2, 2, 4, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 11, 2, 7, 3, 2, 2, 4, 2, 2, 2, 3, 2, 2, 2, 5, 2, 2, 2, 3, 2, 2, 2, 2, 2, 12, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 8, 2, 3, 2, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Greatest common divisor of all prime-exponents in canonical factorization of n-th perfect power. - Reinhard Zumkeller, Oct 13 2002 Asymptotically, 100% of the terms are 2, since the density of cubes and higher powers among the squares and higher powers is 0. - Daniel Forgues, Jul 22 2014 LINKS Daniel Forgues, Table of n, a(n) for n=1..10000 FORMULA a(n) = A052409(A001597(n)). - Reinhard Zumkeller, Oct 13 2002 A001597(n) = A025478(n)^a(n). - Reinhard Zumkeller, Mar 28 2014 MAPLE N:= 10^6: # to get terms corresponding to all perfect powers <= N V:= Vector(N, storage=sparse); V[1]:= 2: for p from 2 to ilog2(N) do   V[[seq(i^p, i=2..floor(N^(1/p)))]]:= p od: r, c, A := ArrayTools:-SearchArray(V): convert(A, list); # Robert Israel, Apr 25 2017 MATHEMATICA Prepend[DeleteCases[#, 0], 2] &@ Table[If[Set[e, GCD @@ #[[All, -1]]] > 1, e, 0] &@ FactorInteger@ n, {n, 10^4}] (* Michael De Vlieger, Apr 25 2017 *) PROG (Haskell) a025479 n = a025479_list !! (n-1)  -- a025479_list is defined in A001597. -- Reinhard Zumkeller, Mar 28 2014, Jul 15 2012 (PARI) print1(2, ", "); for(k=2, 3^8, if(j=ispower(k), print1(j, ", "))) \\ Hugo Pfoertner, Jan 01 2019 CROSSREFS Cf. A001597, A025478, A052409, A124010, A322969. Sequence in context: A305461 A043261 A157986 * A093640 A320538 A343650 Adjacent sequences:  A025476 A025477 A025478 * A025480 A025481 A025482 KEYWORD easy,nonn AUTHOR EXTENSIONS Definition corrected by Daniel Forgues, Mar 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 September 26 15:47 EDT 2021. Contains 347668 sequences. (Running on oeis4.)