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A219346 Pseudoprimes to base 2 that are divisible by the squares of at least two primes. 5
4578627124156945861, 57406119388190085241, 71879404939979986441, 98654983210791303661, 109509947374633729561, 153653468307592928221, 213717603347521018201, 541537521095562280381, 608114634633795825901, 721729926215346550321, 1062575800959998723581 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
2-pseudoprimes of the form n*p^2*q^2, where p and q are distinct Wieferich primes (A001220).
Unless there are other Wieferich primes besides 1093 and 3511, the sequence is the intersection of A247830 and A247831. - Max Alekseyev, Nov 26 2017
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
PROG
(PARI) forstep(n=236641458619975501, 4.489e31, 723664277589495060, if(Mod(2, n)^(n-1)==1, print1(n", ")))
CROSSREFS
Subsequence of each of the following sequences: A158358, A247830, A247831.
Sequence in context: A324207 A288289 A104839 * A246253 A003812 A003805
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 29 03:51 EDT 2024. Contains 371264 sequences. (Running on oeis4.)