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!)
A275029 Partition numbers (A000041) congruent to 2 (mod 4). 7

%I #23 Nov 18 2016 12:55:52

%S 2,22,30,42,490,1002,1958,3010,3718,6842,12310,37338,53174,89134,

%T 105558,124754,204226,614154,1741630,2012558,13848650,34262962,

%U 133230930,214481126,271248950,607163746,4835271870,30388671978,45060624582,88751778802,107438159466

%N Partition numbers (A000041) congruent to 2 (mod 4).

%C Partition numbers having the same number of even divisors as odd divisors.

%C The corresponding indices are in A237280.

%C The intersection of A000041 and A016825.

%H Robert Israel, <a href="/A275029/b275029.txt">Table of n, a(n) for n = 1..500</a>

%e 30 is in the sequence because it is a partition number, and its divisors are [1,2,3,5,6,10,15,30].

%p select(t -> t mod 4 = 2, map(combinat:-numbpart, [$1..500])); # _Robert Israel_, Nov 14 2016

%t Select[PartitionsP@ Range@ 160, Mod[#, 4] == 2 &] (* _Michael De Vlieger_, Nov 15 2016 *)

%o (PARI) a000041(n) = numbpart(n)

%o terms(n) = my(i=0, k=2); while(1, if(Mod(a000041(k), 4)==2, print1(a000041(k), ", "); i++); if(i==n, break); k++)

%o /* Print initial 50 terms as follows */

%o terms(50) \\ _Felix Fröhlich_, Nov 15 2016

%Y Cf. A000041, A016825, A213179, A237280.

%K nonn

%O 1,1

%A _Colin Barker_, Nov 13 2016

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 23 03:30 EDT 2024. Contains 371906 sequences. (Running on oeis4.)