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!)
A122401 Subsequence of A074139 omitting values derived from partitions with a part of size 1. 2

%I #8 Aug 28 2018 13:56:24

%S 1,3,4,5,9,6,12,7,15,16,27,8,18,20,36,9,21,24,25,45,48,81,10,24,28,30,

%T 54,60,64,108,11,27,32,35,63,36,72,75,80,135,144,243,12,30,36,40,72,

%U 42,84,90,96,162,100,180,192,324,13,33,40,45,81,48,96,49,105,112,189,108,120,216,125,225,240,405,256,432,729,14,36,44,50,90,54

%N Subsequence of A074139 omitting values derived from partitions with a part of size 1.

%C When viewed as a table, row sums are given by sequence A079274.

%C Corresponds to members of A036035 which are also powerful numbers (A001694).

%e The two cyclic partitions of five are 5 and 3+2 yielding (5+1)=6 and (3+1)*(2+1) = 4*3 = 12

%e The array begins

%e 1

%e (empty)

%e 3

%e 4

%e 5 9

%e 6 12

%e 7 15 16 27

%e 8 18 20 36

%p A122401_row := proc(n)

%p local e, a,L;

%p L := [] ;

%p for e in ListTools[Reverse](partition(n)) do

%p if member(1,e) then

%p ;

%p else

%p a := 1;

%p for p in e do

%p a := a*(p+1) ;

%p end do:

%p L := [op(L),a] ;

%p end if;

%p end do:

%p L ;

%p end proc:

%p seq(A122401_row(i), i=0..15); # _R. J. Mathar_, Aug 28 2018

%Y Cf. A122172 A079274 A122402, A316532.

%K easy,nonn,tabf

%O 0,2

%A _Alford Arnold_, Sep 01 2006

%E Extended by _R. J. Mathar_, Aug 28 2018

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 April 19 09:23 EDT 2024. Contains 371782 sequences. (Running on oeis4.)