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A328478 Divide n by the largest primorial that divides it and repeat until a fixed point is reached; a(n) is the fixed point. 4
1, 1, 3, 1, 5, 1, 7, 1, 9, 5, 11, 1, 13, 7, 15, 1, 17, 3, 19, 5, 21, 11, 23, 1, 25, 13, 27, 7, 29, 1, 31, 1, 33, 17, 35, 1, 37, 19, 39, 5, 41, 7, 43, 11, 45, 23, 47, 1, 49, 25, 51, 13, 53, 9, 55, 7, 57, 29, 59, 1, 61, 31, 63, 1, 65, 11, 67, 17, 69, 35, 71, 1, 73, 37, 75, 19, 77, 13, 79, 5, 81, 41, 83, 7, 85, 43, 87, 11, 89 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..30030

Index entries for sequences related to primorial numbers

FORMULA

If A111701(n) == n, then a(n) = n, otherwise a(n) = a(A111701(n)).

a(n) = n / A328479(n).

PROG

(PARI)

A111701(n) = forprime(p=2, , if(n%p, return(n), n /= p));

A328478(n) = { my(u=A111701(n)); if(u==n, return(n), return(A328478(u))); };

CROSSREFS

Cf. A007814 (gives the number of iterations to reach a fixed point), A025487 (indices of 1's).

Cf. A002110, A053589, A111701, A328479.

Cf. also A093411 for analogous sequence.

Sequence in context: A339421 A336898 A300330 * A093411 A147088 A340083

Adjacent sequences:  A328475 A328476 A328477 * A328479 A328480 A328481

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 19 2019

EXTENSIONS

Definition clarified by N. J. A. Sloane, Jan 19 2021

STATUS

approved

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Last modified April 18 04:49 EDT 2021. Contains 343072 sequences. (Running on oeis4.)