cp's OEIS Frontend

A064615 Numbers of the form m * 6^k for k >= 0 and m > 0 with gcd(m, 6) = 1.

%I A064615 #23 Sep 08 2022 08:45:04
%S A064615 1,5,6,7,11,13,17,19,23,25,29,30,31,35,36,37,41,42,43,47,49,53,55,59,
%T A064615 61,65,66,67,71,73,77,78,79,83,85,89,91,95,97,101,102,103,107,109,113,
%U A064615 114,115,119,121,125,127,131,133,137,138,139,143,145,149,150,151,155
%N A064615 Numbers of the form m * 6^k for k >= 0 and m > 0 with gcd(m, 6) = 1.
%C A064615 These are the fixed points of A064614, a permutation of natural numbers: A064614(a(n)) = a(n), for all n.
%C A064615 Numbers n such that exponent of highest power of 2 dividing n is equal to exponent of highest power of 3 dividing n. - _Juri-Stepan Gerasimov_, Sep 01 2016
%C A064615 All primes >3 are terms. - _Zak Seidov_, Sep 02 2016
%H A064615 Amiram Eldar, <a href="/A064615/b064615.txt">Table of n, a(n) for n = 1..10000</a>
%F A064615 a(n) = 5n/2 + O(log n). - _Charles R Greathouse IV_, Sep 02 2016
%p A064615 q:= n-> is(padic[ordp](n, 2)=padic[ordp](n, 3)):
%p A064615 select(q,[$1..200])[];  # _Alois P. Heinz_, Oct 28 2021
%t A064615 okQ[n_] := IntegerExponent[n, 2] == IntegerExponent[n, 3];
%t A064615 Select[Range[200], okQ] (* _Jean-François Alcover_, Oct 28 2021 *)
%o A064615 (PARI) is(n)=valuation(n,2)==valuation(n,3) \\ _Charles R Greathouse IV_, Sep 02 2016
%o A064615 (Magma) [n: n in [1..200] |Valuation(n, 2) eq Valuation(n, 3)]; // _Vincenzo Librandi_, Sep 02 2016
%Y A064615 Cf. A064614.
%K A064615 nonn
%O A064615 1,2
%A A064615 _Reinhard Zumkeller_, Sep 25 2001