A155911 - OEIS

%I #16 Jan 19 2019 22:18:04

%S 22,24,54,62,63,82,84,96,104,122,142,153,184,202,204,216,234,262,273,

%T 294,302,333,336,343,344,362,363,364,382,405,414,416,422,423,424,444,

%U 482,483,484,486,502,542,562,564,584,603,622,644,662,663,664,675,714

%N Composite numbers with final digit = number of prime factors (with multiplicity).

%C 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

%H Charles R Greathouse IV, <a href="/A155911/b155911.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) ~ k*n log n/(log log n)^8 with k = 1/161280. - _Charles R Greathouse IV_, Jan 02 2013

%p 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

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

%o (PARI) is(n)=!isprime(n) && bigomega(n)==n%10 \\ _Charles R Greathouse IV_, Jan 02 2013

%Y Cf. A002808.

%K nonn,base

%O 1,1

%A _Juri-Stepan Gerasimov_, Jan 30 2009

%E Extended by _R. J. Mathar_, Jan 31 2009

%E Name clarified by _Harvey P. Dale_ and _Charles R Greathouse IV_, Jan 02 2013