A099208 - OEIS

A099208

In canonical prime-factorization of n replace prime(k)^e with prime(k+e-1).

1, 2, 3, 3, 5, 6, 7, 5, 5, 10, 11, 9, 13, 14, 15, 7, 17, 10, 19, 15, 21, 22, 23, 15, 7, 26, 7, 21, 29, 30, 31, 11, 33, 34, 35, 15, 37, 38, 39, 25, 41, 42, 43, 33, 25, 46, 47, 21, 11, 14, 51, 39, 53, 14, 55, 35, 57, 58, 59, 45, 61, 62, 35, 13, 65, 66, 67, 51, 69, 70, 71, 25, 73, 74

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OFFSET

1,2

COMMENTS

a(n)<=n; a(n)=n iff n is a squarefree number: a(A005117(n))=A005117(n) and a(A013929(n)) < A013929(n);

A099209 = a(a(n)).

LINKS

Table of n, a(n) for n=1..74.

EXAMPLE

a(75) = a(3^1 * 5^2) =

A000040(A049084(3)+1-1)*A000040(A049084(5)+2-1) =

A000040(2+1-1)*A000040(3+2-1) = A000040(2)*A000040(4) = 3*7 = 21.

MATHEMATICA

a[n_] := Times @@ (FactorInteger[n] /. {p_Integer, e_Integer} -> Prime[ PrimePi[p] + e - 1]); a[1] = 1; Array[a, 100] (* Jean-François Alcover, Dec 07 2016 *)

CROSSREFS

Sequence in context: A003967 A349390 A099209 * A331299 A052274 A353842

Adjacent sequences: A099205 A099206 A099207 * A099209 A099210 A099211

KEYWORD

nonn,mult

AUTHOR

Reinhard Zumkeller, Oct 05 2004

STATUS

approved