login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A121061 Numbers n such that n-th partition number A000041(n) is a 3-almost prime (A014612). 0

%I #7 Jul 11 2015 11:21:59

%S 9,10,16,18,20,22,25,29,31,34,37,42,45,48,50,56,57,60,63,69,71,72,73,

%T 83,85,91,101,102,112,113,114,119,139,144,148,151,155,156,172,175,183,

%U 185,190,192,195,202,208,217,238,242,244,245,247,256,257,272,275,291,293

%N Numbers n such that n-th partition number A000041(n) is a 3-almost prime (A014612).

%C 3-almost prime analog of: A046063 Numbers n such that n-th partition number A000041(n) is prime; A065729 n-th partition number (A000041[n]) is a semiprime. See also A065728 Partition numbers (A000041) that are semiprimes (A001358).

%F A000041(a(n)) in A014612.

%e a(1) = 9 because P(9) = 30 = 2 * 3 * 5.

%e a(2) = 10 because P(10) = 42 = 2 * 3 * 7.

%e a(3) = 16 because P(16) = 231 = 3 * 7 * 11.

%Y Cf. A000041, A046063, A065728, A065729.

%K easy,nonn

%O 1,1

%A _Jonathan Vos Post_, Aug 09 2006

%E 112 and 113 inserted by _R. J. Mathar_, Dec 22 2010

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 19 03:14 EDT 2024. Contains 375284 sequences. (Running on oeis4.)