A364255 - OEIS

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A364255

a(n) = gcd(n, A163511(n)).

18

1, 1, 2, 3, 4, 1, 6, 1, 8, 9, 2, 1, 12, 1, 2, 1, 16, 1, 18, 1, 4, 3, 2, 1, 24, 5, 2, 1, 4, 1, 2, 1, 32, 3, 2, 5, 36, 1, 2, 1, 8, 1, 6, 1, 4, 3, 2, 1, 48, 1, 10, 1, 4, 1, 2, 11, 8, 3, 2, 1, 4, 1, 2, 1, 64, 1, 6, 1, 4, 3, 10, 1, 72, 1, 2, 5, 4, 7, 2, 1, 16, 27, 2, 1, 12, 5, 2, 1, 8, 1, 6, 1, 4, 3, 2, 1, 96, 1, 2, 1, 20, 1, 2, 1, 8, 105

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

OFFSET

0,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..16383

Index entries for sequences related to binary expansion of n

FORMULA

From Antti Karttunen, Sep 01 2023: (Start)

a(n) = gcd(n, A364258(n)) = gcd(A163511(n), A364258(n)).

a(n) = n / A364491(n) = A163511(n)/ A364492(n).

(End)

PROG

(Python)

from math import gcd

from sympy import nextprime

def A364255(n):

c, p, k = 1, 1, n

while k:

c *= (p:=nextprime(p))**(s:=(~k&k-1).bit_length())

k >>= s+1

return gcd(c*p, n) # Chai Wah Wu, Jul 25 2023

(PARI)

A163511(n) = if(!n, 1, my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p));

A364255(n) = gcd(n, A163511(n)); \\ Antti Karttunen, Sep 01 2023

CROSSREFS

Cf. A163511, A364257 (Dirichlet inverse), A364258, A364491, A364492, A364493.

Cf. also A364254, A364256, A339969, A364500, A364949.

Sequence in context: A340087 A239223 A143771 * A366283 A065331 A066262

Adjacent sequences: A364252 A364253 A364254 * A364256 A364257 A364258

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 16 2023

STATUS

approved