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!)
 A053585 If n = p_1^e_1 * ... * p_k^e_k, p_1 < ... < p_k primes, then a(n) = p_k^e_k. 25
 1, 2, 3, 4, 5, 3, 7, 8, 9, 5, 11, 3, 13, 7, 5, 16, 17, 9, 19, 5, 7, 11, 23, 3, 25, 13, 27, 7, 29, 5, 31, 32, 11, 17, 7, 9, 37, 19, 13, 5, 41, 7, 43, 11, 5, 23, 47, 3, 49, 25, 17, 13, 53, 27, 11, 7, 19, 29, 59, 5, 61, 31, 7, 64, 13, 11, 67, 17, 23, 7, 71, 9, 73, 37, 25, 19, 11, 13, 79 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Let p be the largest prime dividing n, a(n) is the largest power of p dividing n. LINKS T. D. Noe, Table of n, a(n) for n = 1..1000 FORMULA a(n) = A006530(n)^A071178(n). - Reinhard Zumkeller, Aug 27 2011 a(n) = A141809(n,A001221(n)). - Reinhard Zumkeller, Jan 29 2013 EXAMPLE a(42)=7 because 42=2*3*7, a(144)=9 because 144=16*9=2^4*3^2. MATHEMATICA Table[Power @@ Last @ FactorInteger @ n, {n, 79}] (* Jean-François Alcover, Apr 01 2011 *) PROG (Haskell) a053585 = last . a141809_row  -- Reinhard Zumkeller, Jan 29 2013 (PARI) a(n)=if(n>1, my(f=factor(n)); f[#f~, 1]^f[#f~, 2], 1) \\ Charles R Greathouse IV, Nov 10 2015 (Python) from sympy import factorint, primefactors def a(n):     if n==1: return 1     p = primefactors(n)[-1]     return p**factorint(n)[p] # Indranil Ghosh, May 19 2017 CROSSREFS Cf. A020639, A006530, A034684, A028233, A051119, A008475. Different from A034699. Sequence in context: A319677 A294650 A323129 * A305007 A098988 A274346 Adjacent sequences:  A053582 A053583 A053584 * A053586 A053587 A053588 KEYWORD nonn,easy,nice AUTHOR Frederick Magata (frederick.magata(AT)uni-muenster.de), Jan 19 2000 EXTENSIONS More terms from Andrew Gacek (andrew(AT)dgi.net), Apr 20 2000 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 April 5 23:19 EDT 2020. Contains 333260 sequences. (Running on oeis4.)