A059485 - OEIS

A059485

Highest prime factor is greater than 3.

5, 7, 10, 11, 13, 14, 15, 17, 19, 20, 21, 22, 23, 25, 26, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 82, 83, 84, 85, 86, 87, 88, 89

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Numbers n such that A006530(n) > 3. - Felix Fröhlich, Dec 22 2016

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..9933

FORMULA

a(n) ~ n. - Charles R Greathouse IV, Jul 06 2016

MATHEMATICA

fQ[n_]:=! PowerMod[6, n, n]==0; Select[Range [100], fQ] (* Vincenzo Librandi, Dec 22 2016 *)

PROG

(PARI) is(n)=n>>=valuation(n, 2); n/=3^valuation(n, 3); n>1 \\ Charles R Greathouse IV, Jul 06 2016; corrected by Michel Marcus, May 19 2022

(Magma) [n: n in [1..100] | not PrimeDivisors(n) subset [2, 3]]; // Vincenzo Librandi, Dec 22 2016

(Python)

from sympy import integer_log

def A059485(n):

def f(x): return n+sum((x//3**i).bit_length() for i in range(integer_log(x, 3)[0]+1))

m, k = n, f(n)

while m != k: m, k = k, f(k)

return m # Chai Wah Wu, Sep 16 2024

CROSSREFS

Complement of A003586. Cf. A007310 for numbers whose smallest prime factor (if there is one) is greater than 3.

Cf. A006530.

Sequence in context: A264349 A320114 A364284 * A028786 A282391 A080760

Adjacent sequences: A059482 A059483 A059484 * A059486 A059487 A059488

KEYWORD

nonn,easy

AUTHOR

Simone Caramel (simonecaramel(AT)libero.it), Feb 04 2001

EXTENSIONS

More terms from Henry Bottomley, Feb 05 2001

STATUS

approved