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A036327 Composite numbers n such that juxtaposition of prime factors of n has length 3. 2

%I #11 Feb 21 2019 23:16:28

%S 8,12,18,20,22,26,27,28,30,33,34,38,39,42,45,46,50,51,55,57,58,62,63,

%T 65,69,70,74,75,77,82,85,86,87,91,93,94,95,98,105,106,111,115,118,119,

%U 122,123,125,129,133,134,141,142,145,146,147,155,158,159,161,166,175

%N Composite numbers n such that juxtaposition of prime factors of n has length 3.

%C The last term is a(104)=679.

%H Nathaniel Johnston, <a href="/A036327/b036327.txt">Table of n, a(n) for n = 1..104</a> (full sequence)

%p isA036327 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=3, n, NULL): end: seq(isA036327(n),n=2..999); # _Nathaniel Johnston_, Jun 22 2011

%Y Cf. A036326-A036334.

%K nonn,base,easy,fini,full

%O 1,1

%A _Patrick De Geest_, Dec 15 1998

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Last modified April 25 11:39 EDT 2024. Contains 371969 sequences. (Running on oeis4.)