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Revision History for A342012

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Showing entries 1-10 | older changes
Primorial deflation of the n-th colossally abundant number: the unique integer k such that A108951(k) = A004490(n).
(history; published version)
#16 by Alois P. Heinz at Fri May 20 05:25:49 EDT 2022
STATUS

reviewed

approved

#15 by Michel Marcus at Fri May 20 03:34:44 EDT 2022
STATUS

proposed

reviewed

#14 by Amiram Eldar at Fri May 20 03:06:33 EDT 2022
STATUS

editing

proposed

#13 by Amiram Eldar at Fri May 20 02:55:05 EDT 2022
LINKS

Amiram Eldar, <a href="/A342012/b342012.txt">Table of n, a(n) for n = 1..10000</a>

STATUS

approved

editing

#12 by Susanna Cuyler at Sat Mar 13 18:08:21 EST 2021
STATUS

proposed

approved

#11 by Antti Karttunen at Sat Mar 13 13:34:18 EST 2021
STATUS

editing

proposed

#10 by Antti Karttunen at Sat Mar 13 13:01:38 EST 2021
COMMENTS

In contrast to A329902, this sequence is monotonic. Proof: , because each term is obtained from the previous, either by multiplying it by 2, or by "bumping" one [or hypothetically: two] of its prime factors one step up (i.e., replacing it with the next larger prime). Both , and both operations are guaranteed to make the number larger, therefore each term is strictly larger than the previous.

#9 by Antti Karttunen at Sat Mar 13 07:08:52 EST 2021
COMMENTS

In contrast to A329902, this sequence is monotonic. Proof: each term is obtained from the previous, either by multiplying it by 2, or by "bumping" one [or hypothetically: two] of its prime factors one step up (i.e., replacing it with the next larger prime). Both steps operations are guaranteed to increase make the number, therefor larger, therefore each term is strictly larger than the previous.

PROG

\\ Or alternatively, using:

A329900(n) = { my(m=1, pp=1); while(1, forprime(p=2, , if(n%p, if(2==p, return(m), break), n /= p; pp = p)); m *= pp); (m); };

A342012(n) = A329900(A004490(n));

#8 by Antti Karttunen at Fri Mar 12 23:06:19 EST 2021
COMMENTS

In contrast to A329902, this sequence is monotonic. Proof: each term is obtained from the previous, either by multiplying it by 2, or by "bumping" one [or hypothetically: two] of its prime factors one step up (i.e., replacing it with the next larger prime). Both steps are guaranteed to grow increase the number, therefor each term is strictly larger than the previous.

CROSSREFS

Cf. also A217867, A329902.

#7 by Antti Karttunen at Mon Mar 08 18:29:26 EST 2021
COMMENTS

In contrast to A329902, this sequence is monotonic. Proof: each term is obtained from the previous, either by multiplying it by 2, or by "bumping" one [or hypothetically: two] of its prime factors one step up (i.e., replacing it with the next larger prime). Both steps are guaranteed to grow the number, therefor each term is strictly larger than the previous.