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A155911 Composite numbers with final digit = number of prime factors (with multiplicity). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

a(n) ~ k*n log n/(log log n)^8 with k = 1/161280. - Charles R Greathouse IV, Jan 02 2013

MAPLE

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: # R. J. Mathar, Jan 31 2009

MATHEMATICA

With[{upto=800}, Select[Complement[Range[upto], Prime[Range[ PrimePi[ upto]]]], Last[ IntegerDigits[#]] ==PrimeOmega[#]&]] (* Harvey P. Dale, Nov 29 2011 *)

PROG

(PARI) is(n)=!isprime(n) && bigomega(n)==n%10 \\ Charles R Greathouse IV, Jan 02 2013

CROSSREFS

Cf. A002808.

Sequence in context: A244397 A138603 A181454 * A061411 A053779 A177734

Adjacent sequences:  A155908 A155909 A155910 * A155912 A155913 A155914

KEYWORD

nonn,base

AUTHOR

Juri-Stepan Gerasimov, Jan 30 2009

EXTENSIONS

Extended by R. J. Mathar, Jan 31 2009

Name clarified by Harvey P. Dale and Charles R Greathouse IV, Jan 02 2013

STATUS

approved

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Last modified November 24 18:11 EST 2020. Contains 338616 sequences. (Running on oeis4.)