The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A025473 a(1) = 1; for n > 1, a(n) = prime root of n-th prime power (A000961). 29
 1, 2, 3, 2, 5, 7, 2, 3, 11, 13, 2, 17, 19, 23, 5, 3, 29, 31, 2, 37, 41, 43, 47, 7, 53, 59, 61, 2, 67, 71, 73, 79, 3, 83, 89, 97, 101, 103, 107, 109, 113, 11, 5, 127, 2, 131, 137, 139, 149, 151, 157, 163, 167, 13, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence is related to the cyclotomic sequences A013595 and A020500, leading to the procedure used in the Mathematica program. - Roger L. Bagula, Jul 08 2008 From Reinhard Zumkeller, Jun 26 2011: (Start) A000961(n) = a(n)^A025474(n); A056798(n) = a(n)^(2*A025474(n)); A192015(n) = A025474(n)*a(n)^(A025474(n)-1). (End) "LCM numeral system": a(n+1) is radix for index n, n >= 0; a(-n+1) is 1/radix for index n, n < 0. - Daniel Forgues, May 03 2014 REFERENCES Paul J. McCarthy, Algebraic Extensions of Fields, Dover books, 1976, pages 40, 69 LINKS David Wasserman, Table of n, a(n) for n = 1..1000 OEIS Wiki, LCM numeral system Eric Weisstein's World of Mathematics, Cyclotomic Polynomial FORMULA a(n) = A006530(A000961(n)) = A020639(A000961(n)). - David Wasserman, Feb 16 2006 MAPLE cvm := proc(n, level) local f, opf; if n < 2 then RETURN() fi; f := ifactors(n); opf := op(1, op(2, f)); if nops(op(2, f)) > 1 or op(2, opf) <= level then RETURN() fi; op(1, opf) end: A025473_list := n -> [1, seq(cvm(i, 0), i=1..n)]; A025473_list(240); # Peter Luschny, Sep 21 2011 MATHEMATICA a = Join[{1}, Flatten[Table[If[PrimeQ[Apply[Plus, CoefficientList[Cyclotomic[n, x], x]]], Apply[Plus, CoefficientList[Cyclotomic[n, x], x]], {}], {n, 1, 1000}]]] (* Roger L. Bagula, Jul 08 2008 *) Join[{1}, First@ First@# & /@ FactorInteger@ Select[Range@ 240, PrimePowerQ]] (* Robert G. Wilson v, Aug 17 2017 *) PROG (Sage) def A025473_list(n) : R = [1] for i in (2..n) : if i.is_prime_power() : R.append(prime_divisors(i)[0]) return R A025473_list(239) # Peter Luschny, Feb 07 2012 (Haskell) a025473 = a020639 . a000961 -- Reinhard Zumkeller, Aug 14 2013 (PARI) print1(1); for(n=2, 1e3, if(isprimepower(n, &p), print1(", "p))) \\ Charles R Greathouse IV, Apr 28 2014 CROSSREFS Cf. A013595, A020500, A025476. Sequence in context: A286151 A192138 A175264 * A351847 A192141 A092556 Adjacent sequences: A025470 A025471 A025472 * A025474 A025475 A025476 KEYWORD easy,nonn,nice AUTHOR David W. Wilson, Dec 11 1999 EXTENSIONS Offset corrected by David Wasserman, Dec 22 2008 STATUS approved

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

Last modified January 29 23:01 EST 2023. Contains 359939 sequences. (Running on oeis4.)