A283069 A283050(n) divided by the square of its least prime factor.

1, 2, 1, 3, 4, 5, 6, 1, 3, 7, 8, 9, 10, 11, 5, 12, 1, 13, 14, 15, 7, 16, 17, 18, 19, 20, 9, 21, 22, 23, 24, 11, 25, 26, 27, 28, 29, 13, 30, 1, 31, 5, 32, 33, 15, 34, 35, 36, 37, 38, 17, 39, 40, 41, 42, 1, 19, 43, 7, 44, 45, 46, 47, 21, 48, 49, 50, 51, 23, 52, 53

Offset

1,2

Comments

Sequence contains all positive integers. Every positive integer except 1 can be term of this sequence only finitely many times (i.e., 8 is a term only for a(11) = 8). - Altug Alkan, Feb 28 2017

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Ana Rechtman, Février 2017, 4e défi, Images des Mathématiques, CNRS, 2017.

Formula

a(n) = A283050(n) / A020639(A283050(n))^2. - Altug Alkan, Feb 28 2017

Maple

Res:= NULL:
for n from 2 to 1000 do
  p:= min(numtheory:-factorset(n));
  if n mod p^2 = 0 then Res:= Res, n/p^2; fi
od:
Res; # Robert Israel, Feb 28 2017

Mathematica

DeleteCases[Table[n/FactorInteger[n][[1, 1]]^2, {n, 2, 300}], k_ /; ! IntegerQ@ k] (* Michael De Vlieger, Feb 28 2017 *)

Prog

(PARI) lista(nn) = {for(n=2, nn, if (!(n % (p=factor(n)[1, 1]^2)), print1(n/p, ", ")); ); }

Crossrefs

Cf. A126773, A283050.

Sequence in context: A101204 A169808 A328395 * A304528 A360585 A175499

Adjacent sequences: A283066 A283067 A283068 * A283070 A283071 A283072

Keyword

nonn,look

Author

Michel Marcus, Feb 28 2017

Status

approved