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A128285
Numbers of the form m = p1 * p2 * p3 * p4 where for each d|m we have (d+m/d)/2 prime and p1 < p2 < p3 < p4 each prime.
5
1365, 4305, 10465, 11685, 15873, 27105, 31845, 35245, 50065, 54033, 58765, 74965, 84513, 91977, 95557, 95613, 96033, 104377, 113997, 114405, 117957, 118105, 126357, 127605, 136437, 170905, 197985, 209605, 215373, 226185, 248385, 277797
OFFSET
1,1
LINKS
EXAMPLE
1365=3 * 5 * 7 * 13 and (3 * 5 * 7 * 13+1)/2, (3+5 * 7 * 13)/2, (5+3 * 7 * 13)/2, (7+3 * 5 * 13)/2, (13+3 * 5 * 7)/2, (3 * 5+7.13)/2, (3 * 7+5 * 13)/2, (3 * 13+5 * 7)/2 are all primes and 1365 is the smallest such integer which is the product of 4 primes, so 1365 is in the sequence.
CROSSREFS
Subsequence of A046390.
Sequence in context: A043578 A004970 A234501 * A069310 A096117 A140936
KEYWORD
nonn
AUTHOR
Kok Seng Chua (chuakokseng(AT)hotmail.com), Mar 05 2007
EXTENSIONS
New name from David A. Corneth, Jan 09 2021
STATUS
approved