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A155911
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Composite numbers with final digit = number of prime factors (with multiplicity).
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1
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22, 24, 54, 62, 63, 82, 84, 96, 104, 122, 142, 153, 184, 202, 204, 216, 234, 262, 273, 294, 302, 333, 336, 343, 344, 362, 363, 364, 382, 405, 414, 416, 422, 423, 424, 444, 482, 483, 484, 486, 502, 542, 562, 564, 584, 603, 622, 644, 662, 663, 664, 675, 714
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listen;
history;
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internal format)
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OFFSET
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1,1
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COMMENTS
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Almost all numbers in this sequence are 9 mod 10. The first such number is a(10589) = 124659. - Charles R Greathouse IV, Jan 02 2013
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LINKS
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Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) ~ kn log n/(log log n)^8 with k = 1/161280. - Charles R Greathouse IV, Jan 02 2013
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MAPLE
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A010879 := proc(n) n mod 10 ; end: A001222 := proc(n) numtheory[bigomega](n); end: for n from 4 to 2000 do if not isprime(n) then if A010879(n) = A001222(n) then printf("%d, ", n) ; fi; fi; od: [From R. J. Mathar, Jan 31 2009]
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MATHEMATICA
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With[{upto=800}, Select[Complement[Range[upto], Prime[Range[ PrimePi[ upto]]]], Last[ IntegerDigits[#]] ==PrimeOmega[#]&]] (* From Harvey P. Dale, Nov 29 2011 *)
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PROG
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(PARI) is(n)=!isprime(n) && bigomega(n)==n%10 \\ Charles R Greathouse IV, Jan 02 2013
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CROSSREFS
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Cf. A002808.
Sequence in context: A030593 A138603 A181454 * A061411 A053779 A177734
Adjacent sequences: A155908 A155909 A155910 * A155912 A155913 A155914
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KEYWORD
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nonn,base,changed
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AUTHOR
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Juri-Stepan Gerasimov, Jan 30 2009
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EXTENSIONS
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Extended by R. J. Mathar, Jan 31 2009
Name clarified by Harvey P. Dale and Charles R Greathouse IV, Jan 02 2013
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STATUS
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approved
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