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A134602 Composite numbers such that the square mean of their prime factors is a nonprime integer (where the prime factors are taken with multiplicity and the square mean of c and d is sqrt((c^2+d^2)/2)). 19
378, 455, 527, 918, 1265, 1615, 2047, 2145, 2175, 2345, 2665, 3713, 3835, 4207, 4305, 4633, 5000, 5117, 5382, 6061, 6678, 6887, 6965, 7055, 7267, 7327, 7497, 7685, 7791, 8470, 8785, 8918, 9641, 10205, 10545, 10647, 11137, 11543, 11713, 13482, 14079 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Numbers included in A134600, but not in A134601. a(1)=378 is the minimal number with this property.
Also numbers included in A134603, but not in A134604.
LINKS
EXAMPLE
a(2)=455, since 455=5*7*13 and sqrt((5^2+7^2+13^2)/3)=sqrt(81)=9.
CROSSREFS
Sequence in context: A045197 A349539 A098835 * A268373 A030029 A064242
KEYWORD
nonn
AUTHOR
Hieronymus Fischer, Nov 11 2007
EXTENSIONS
Definition clarified by Hieronymus Fischer, Apr 20 2013, Jun 01 2013
STATUS
approved

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Last modified April 23 22:36 EDT 2024. Contains 371917 sequences. (Running on oeis4.)