cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A049575 Prime partition numbers.

Original entry on oeis.org

2, 3, 5, 7, 11, 101, 17977, 10619863, 6620830889, 80630964769, 228204732751, 1171432692373, 1398341745571, 10963707205259, 15285151248481, 10657331232548839, 790738119649411319, 18987964267331664557, 74878248419470886233, 1394313503224447816939
Offset: 1

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Author

Keywords

Crossrefs

Intersection of A000040 and A000041.
Cf. A038753, A065728. - Reinhard Zumkeller, Nov 03 2009

Programs

  • Mathematica
    lst={};Do[a=PartitionsP[n];If[PrimeQ[a],AppendTo[lst,a]],{n,2*6!}];lst (* Vladimir Joseph Stephan Orlovsky, Jun 14 2009 *)
    Select[PartitionsP[Range[1000]],PrimeQ] (* Harvey P. Dale, Mar 11 2013 *)
  • PARI
    for(n=0,10^3,my(p=numbpart(n));if(isprime(p),print1(p,", "))); \\ Joerg Arndt, May 09 2013

Formula

a(n) = A000041(A046063(n)) = A000040(A051143(n)). - M. F. Hasler, Oct 19 2008
A010051(a(n))*A167392(a(n)) = 1. - Reinhard Zumkeller, Nov 03 2009

Extensions

More terms from James Sellers and Christian G. Bower, Oct 15 1999.

A065729 Numbers k such that the k-th partition number (A000041(k)) is a semiprime.

Original entry on oeis.org

7, 8, 12, 23, 65, 67, 76, 81, 87, 90, 92, 93, 95, 121, 123, 143, 146, 161, 181, 203, 218, 220, 235, 241, 251, 252, 287, 321, 330, 388, 406, 423, 437, 438, 443, 455, 456, 507, 555, 594, 603, 626, 646, 661, 665, 672, 685, 707, 708, 715, 720, 755, 808, 837, 856
Offset: 1

Views

Author

Patrick De Geest, Nov 18 2001

Keywords

Examples

			The 808th partition number 8151756509675604512522473567 = 5963320232189 * 1366982853893003.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[900],PrimeOmega[PartitionsP[#]]==2&] (* Harvey P. Dale, Nov 27 2024 *)
  • PARI
    isok(k) = { bigomega(numbpart(k))==2 } \\ Harry J. Smith, Oct 28 2009

Extensions

Offset changed from 0 to 1 by Harry J. Smith, Oct 28 2009
Missing a(38) = 507 added by Harry J. Smith, Oct 28 2009

A121061 Numbers k such that k-th partition number A000041(k) is a 3-almost prime (A014612).

Original entry on oeis.org

9, 10, 16, 18, 20, 22, 25, 29, 31, 34, 37, 42, 45, 48, 50, 56, 57, 60, 63, 69, 71, 72, 73, 83, 85, 91, 101, 102, 112, 113, 114, 119, 139, 144, 148, 151, 155, 156, 172, 175, 183, 185, 190, 192, 195, 202, 208, 217, 238, 242, 244, 245, 247, 256, 257, 272, 275, 291, 293
Offset: 1

Views

Author

Jonathan Vos Post, Aug 09 2006

Keywords

Examples

			a(1) = 9 because P(9) = 30 = 2 * 3 * 5.
a(2) = 10 because P(10) = 42 = 2 * 3 * 7.
a(3) = 16 because P(16) = 231 = 3 * 7 * 11.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[300],PrimeOmega[PartitionsP[#]]==3&] (* James C. McMahon, Oct 12 2024 *)

Formula

A000041(a(n)) in A014612.

Extensions

112 and 113 inserted by R. J. Mathar, Dec 22 2010
Showing 1-3 of 3 results.