The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A141231 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A141231

Positive integers whose prime factorizations contain only primes from A001122.
(history; published version)

#14 by Joerg Arndt at Tue Dec 11 07:07:45 EST 2018

STATUS

reviewed

approved

#13 by G. C. Greubel at Mon Dec 10 13:56:30 EST 2018

STATUS

proposed

reviewed

#12 by Michel Marcus at Mon Dec 10 13:30:45 EST 2018

STATUS

editing

proposed

#11 by Michel Marcus at Mon Dec 10 13:30:20 EST 2018

PROG

isok(n) = {if ((n>1) && (n % 2, ), my(f=factor(n)); #select(x->isokp(x), f[, 1]) == #f~; , , 0); } \\ Michel Marcus, Dec 09 2018

STATUS

proposed

editing

Discussion

Mon Dec 10

13:30

Michel Marcus: I have modified pari to avoid 1 being found as a term

#10 by Jon E. Schoenfield at Sun Dec 09 16:11:10 EST 2018

STATUS

editing

proposed

Discussion

Sun Dec 09

16:45

Michel Marcus: yes better

#9 by Jon E. Schoenfield at Sun Dec 09 16:10:41 EST 2018

NAME

Positive integers n the whose prime factorization of which contains factorizations contain only primes from A001122.

STATUS

proposed

editing

Discussion

Sun Dec 09

16:11

Jon E. Schoenfield: Okay like this?

#8 by Amiram Eldar at Sun Dec 09 15:00:27 EST 2018

STATUS

editing

proposed

Discussion

Sun Dec 09

16:04

G. C. Greubel: The title needs work. "positive integers n" and "the prime .." doesn't blend well. Maybe " Positive integers n whose prime factorizations contain only primes from A001122 " ? Also since 1 is not in A001122 then probably should not be an element here.

#7 by Amiram Eldar at Sun Dec 09 14:59:54 EST 2018

MATHEMATICA

aQ[n_] := Length[Select[FactorInteger[n][[;; , 1]], # > 1 && PrimitiveRoot@# != 2 &]] == 0; Select[Range[2, 250], aQ] (* Amiram Eldar, Dec 09 2018 *)

STATUS

proposed

editing

Discussion

Sun Dec 09

15:00

Amiram Eldar: If added, please change Range[2, 250] to Range[250]

#6 by Amiram Eldar at Sun Dec 09 14:52:05 EST 2018

STATUS

editing

proposed

#5 by Amiram Eldar at Sun Dec 09 14:51:54 EST 2018

MATHEMATICA

aQ[n_] := Length[Select[FactorInteger[n][[;; , 1]], PrimitiveRoot@# != 2 &]] == 0; Select[Range[2, 250], aQ] (* Amiram Eldar, Dec 09 2018 *)

STATUS

proposed

editing