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 1-6 of 6 results.

A051177 Perfectly partitioned numbers: numbers k that divide the number of partitions p(k).

Original entry on oeis.org

1, 2, 3, 124, 158, 342, 693, 1896, 3853, 4434, 5273, 8640, 14850, 17928, 110516, 178984, 274534
Offset: 1

Views

Author

M.A. Muller (mam(AT)land.sun.ac.za)

Keywords

Comments

Are there infinitely many perfectly partitioned numbers? Does there exist some k > 3 for which p(k) is a perfectly partitioned number?
No other terms below 10^8. - Max Alekseyev, May 19 2014
A probabilistic analysis suggests that there are infinitely many terms. - Franklin T. Adams-Watters, Oct 07 2018

Examples

			a(4) = 124 because p(124) = 2841940500 is divisible by 124.
a(7) = 693 because partition number of 693 is 43397921522754943172592795 = 693*62623263380598763596815.
		

References

  • Problem 2464, Journal of Recreational Mathematics 29(4), p. 304.
  • Solution to problem 2464 "Perfect Partitions", Journal of Recreational Mathematics 30(4), pp. 294-295, 1999-2000.

Crossrefs

Cf. A000041.
Cf. A093952 = partition number A000041(n) mod n.

Programs

  • Mathematica
    Do[ If[ Mod[ PartitionsP@n, n] == 0, Print@n], {n, 250000}] (* Robert G. Wilson v *)
    Select[Range[275000],Divisible[PartitionsP[#],#]&] (* Harvey P. Dale, Aug 21 2013~ *)
  • PARI
    for(n=1,20000,if(numbpart(n)%n==0,print1(n,","))) \\ Klaus Brockhaus, Sep 06 2006

Extensions

More terms from Don Reble, Jul 26 2002

A162468 Integers n such that A000009(n) (the number of partitions of n into distinct parts) == 1 (mod n).

Original entry on oeis.org

1, 2, 11, 22, 92, 149, 6919, 25517, 45339, 146635, 167903, 7461583, 14809123, 75788157, 80012043
Offset: 1

Views

Author

Max Alekseyev, Jul 04 2009

Keywords

Comments

Integers n dividing A000009(n)-1.
No other terms below 10^8.

Crossrefs

Extensions

a(1)=1 prepended by Max Alekseyev, Dec 28 2011
a(13)-a(15) from Max Alekseyev, Jul 10 2015

A121015 Numbers n such that partition number p(n) == 14 (mod n).

Original entry on oeis.org

1, 2, 8, 1402, 3579, 4111, 5289, 6383, 6467, 15146, 32141, 41910, 82849, 110088, 127531, 185114, 1320338, 1467242, 5739729, 22507473, 32494198
Offset: 1

Views

Author

Zak Seidov, Sep 02 2006

Keywords

Comments

No other terms below 10^8. - Max Alekseyev, May 19 2014

Examples

			Partition number of 8 is 22 = 1*8 + 14, hence 8 is a term.
Partition number of 1402 is 52435757789401123913939450130086135644 = 37400683159344596229628709079947315*1402 + 14, hence 1402 is a term.
		

Crossrefs

Programs

  • Mathematica
    Do[ If[ Mod[ PartitionsP@n - 14, n] == 0, Print@n], {n, 731000}] (* Robert G. Wilson v, Sep 14 2006 *)
  • PARI
    for(n=1,200000,if((numbpart(n)-14)%n==0,print1(n,","))) \\ Klaus Brockhaus, Sep 07 2006

Extensions

Edited, corrected and extended (a(1) to a(3), a(11) to a(16)) by Klaus Brockhaus, Sep 07 2006
Rechecked by Klaus Brockhaus, Mar 17 2007
a(17)-a(19) from Ryan Propper, Mar 17 2007
a(20) from Max Alekseyev, Dec 28 2011
a(21) from Max Alekseyev, Jan 15 2013

A203023 Integers n dividing A000041(n)+1.

Original entry on oeis.org

1, 6, 156, 305, 484, 1219, 322733, 14343797, 58460571, 68355787
Offset: 1

Views

Author

Max Alekseyev, Dec 27 2011

Keywords

Comments

No other terms below 10^8.

Crossrefs

A056872 Numbers k such that k | p(k) + q(k) where p(k) = partition numbers (A000041) and q(k) = partition numbers into distinct parts (A000009).

Original entry on oeis.org

1, 5, 25, 42, 133, 618, 643, 701, 1962, 8150, 147458, 168459, 356038, 415870, 536685, 637757, 1093612, 1207618, 3368325, 3470706, 23400631, 37621653
Offset: 1

Views

Author

Robert G. Wilson v, Sep 02 2000

Keywords

Comments

No other terms below 10^8. - Max Alekseyev, Oct 12 2023

Crossrefs

Programs

  • Mathematica
    Do[ If[ Mod[ PartitionsP[ n ] + PartitionsQ[ n ], n ] == 0, Print[ n ] ], {n, 1, 8150} ]

Extensions

a(11)-a(18) from Sean A. Irvine, May 12 2022
a(19)-a(22) from Max Alekseyev, Oct 12 2023

A056873 Numbers k such that k | p(k) - q(k) where p(k) = partition numbers (A000041) and q(k) = partition numbers into distinct parts (A000009).

Original entry on oeis.org

1, 8, 11, 34, 310, 1688, 2307, 2708, 13988, 21315, 46739, 426378, 771476, 11762557, 18628390, 19841526, 24396168, 85110245
Offset: 1

Views

Author

Robert G. Wilson v, Sep 02 2000

Keywords

Comments

No other terms below 10^8. - Max Alekseyev, Oct 12 2023

Crossrefs

Programs

  • Mathematica
    Do[ If[ Mod[ PartitionsP[n] - PartitionsQ[n], n] == 0, Print[n]], {n, 1, 14577}]

Extensions

a(10)-a(13) from Sean A. Irvine, May 12 2022
a(14)-a(18) from Max Alekseyev, Oct 12 2023
Showing 1-6 of 6 results.