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A036328
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Composite numbers n such that juxtaposition of prime factors of n has length 4.
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1
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16, 24, 36, 40, 44, 52, 54, 56, 60, 66, 68, 76, 78, 81, 84, 90, 92, 99, 100, 102, 110, 114, 116, 117, 121, 124, 126, 130, 135, 138, 140, 143, 148, 150, 153, 154, 164, 165, 169, 170, 171, 172, 174, 182, 186, 187, 188, 189, 190, 195, 196, 202, 206, 207, 209, 210
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graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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The last term of this sequence is a(1048)=9409.
Prime factors are taken with multiplicity. - Harvey P. Dale, Dec 05 2015
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LINKS
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MAPLE
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isA036328 := 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))=4, n, NULL): end: l:=[seq(isA036328(n), n=2..9999)]; # Nathaniel Johnston, Jun 22 2011
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MATHEMATICA
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jpf4Q[n_]:=Length[Flatten[IntegerDigits/@Table[#[[1]], {#[[2]]}]&/@FactorInteger[n]]]==4; Select[Range[300], jpf4Q] (* Harvey P. Dale, Dec 05 2015 *)
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CROSSREFS
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KEYWORD
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nonn,base,fini,full,easy
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AUTHOR
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STATUS
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approved
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