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 1-10 of 13 results. Next

A114165 Numbers n such that p(2n) is prime, where p(n) is the number of partitions of n.

Original entry on oeis.org

1, 2, 3, 18, 66, 84, 93, 94, 106, 108, 151, 183, 220, 249, 273, 329, 543, 648, 789, 793, 1068, 1251, 1254, 1284, 1366, 1456, 1549, 1584, 1671, 1771, 2059, 2131, 2228, 2331, 2501, 3399, 3729, 4224, 4456, 4646, 4999, 5093, 5540, 6014, 6510, 6736, 7520, 8124
Offset: 1

Views

Author

Robert G. Wilson v, Nov 14 2005

Keywords

Comments

2n-th partition number (A000041(2n)) is prime.

Crossrefs

Programs

  • Mathematica
    Select[ Range[9137], PrimeQ[ PartitionsP[2# ]] &]
  • PARI
    is(n)=isprime(numbpart(2*n)) \\ Charles R Greathouse IV, Feb 17 2017

A067735 Number of partitions of 2^n into distinct parts.

Original entry on oeis.org

1, 1, 2, 6, 32, 390, 16444, 4013544, 11784471548, 1168225267521350, 16816734263788624008200, 276565526698898057002583240473088, 96052644365764024805972019009272150642974291708, 43586702014259316987395017345466711329303914541873541942193666197800
Offset: 0

Views

Author

Henry Bottomley, Mar 11 2002

Keywords

Comments

Always even for n>1 since the only powers of two which are generalized pentagonal numbers (A001318 - needed to produce odd numbers of partitions into distinct terms) are 2^0 and 2^1. Number of digits of A068413 divided by number of digits of a(n) approaches sqrt(2).

Examples

			a(3)=6 since 2^3=8 can be partitioned into 8, 7+1, 6+2, 5+3, 5+2+1, or 4+3+1.
		

Crossrefs

Programs

  • Mathematica
    Table[ PartitionsQ[2^n], {n, 0, 13}]

Formula

a(n) = A000009(A000079(n)).
a(n) ~ exp(Pi*sqrt(2^n/3))/(3^(1/4)*2^(3*n/4+2)). - Ilya Gutkovskiy, Jan 13 2017

A248728 Number of partitions of 3^n.

Original entry on oeis.org

1, 3, 30, 3010, 18004327, 133978259344888, 233202632378520643600875145, 817400077628568283525440629036885986580578161120, 37560309092871894517794668078727801667246369744545646936224413217138060330481863103169
Offset: 0

Views

Author

Robert G. Wilson v, Oct 12 2014

Keywords

Crossrefs

Programs

  • Magma
    [NumberOfPartitions(3^n): n in [0..8]]; // Vincenzo Librandi, Oct 13 2014
    
  • Mathematica
    Table[ PartitionsP[ 3^n], {n, 0, 8}]
  • PARI
    a(n) = numbpart(3^n) \\ Michel Marcus, Oct 18 2014

Formula

a(n) = A000041(3^n). - Michel Marcus, Oct 18 2014
a(n) ~ exp(Pi*sqrt(2*3^(n-1)))/(4*3^(n+1/2)). - Ilya Gutkovskiy, Jan 13 2017

Extensions

Added a(0)=1 from Vincenzo Librandi, Oct 13 2014

A129490 Number of digits in the decimal expansion of the number of partitions of 2^n.

Original entry on oeis.org

1, 1, 1, 2, 3, 4, 7, 10, 15, 22, 32, 47, 67, 97, 138, 197, 280, 398, 565, 801, 1134, 1607, 2275, 3219, 4555, 6445, 9118, 12898, 18243, 25803, 36494, 51615, 72998, 103238, 146005, 206486, 292020, 412982, 584050, 825975, 1168110, 1651962, 2336232
Offset: 0

Views

Author

Robert G. Wilson v, Apr 11 2007

Keywords

Comments

For the same sequence but for base 10 (A070177): A077644.

Crossrefs

Programs

  • Mathematica
    f[n_] := Floor[ Log[10, PartitionsP[2^n]] + 1]; Table[ f@n, {n, 0, 42}]

Formula

See A000041: (Hardy and Ramanujan) & (Ayoub, p. 197).
a(n) = A055642(A068413(n)).
a(n) =~ 2*A129491(n)/9.

Extensions

Missing a(0) prepended by Georg Fischer, Nov 06 2023

A248730 Number of partitions of 5^n.

Original entry on oeis.org

1, 7, 1958, 3163127352, 1606903190858354689128371, 8630901377559029573671524821295260243701883575513498104067
Offset: 0

Views

Author

Robert G. Wilson v, Oct 12 2014

Keywords

Comments

Next term is too big to be included.

Crossrefs

Programs

  • Magma
    [NumberOfPartitions(5^n): n in [0..6]]; // Vincenzo Librandi, Oct 13 2014
  • Mathematica
    Table[ PartitionsP[ 5^n], {n, 0, 6}]
  • PARI
    vector(8, n, n--; numbpart(5^n)) \\ Michel Marcus, Oct 13 2014
    

A248732 Number of partitions of 6^n.

Original entry on oeis.org

1, 11, 17977, 15285151248481, 1398703012615213588677365804960180341, 3173477897288016617984809197028065610087051214582584606785402878333070481745149246796102615681
Offset: 0

Views

Author

Robert G. Wilson v, Oct 12 2014

Keywords

Crossrefs

Programs

  • Magma
    [NumberOfPartitions(6^n): n in [0..6]]; // Vincenzo Librandi, Oct 13 2014
  • Mathematica
    Table[ PartitionsP[ 6^n], {n, 0, 5}]

Formula

A248732 = A000041 o A000400. \\ M. F. Hasler, Oct 16 2014

A248734 Number of partitions of 7^n.

Original entry on oeis.org

1, 15, 173525, 175943559810422753, 229866006383458830949778967121025947053151071434926
Offset: 0

Views

Author

Robert G. Wilson v, Oct 12 2014

Keywords

Comments

Next term is too big to be included.

Crossrefs

Programs

  • Magma
    [NumberOfPartitions(7^n): n in [0..6]]; // Vincenzo Librandi, Oct 13 2014
    
  • Mathematica
    Table[ PartitionsP[ 7^n], {n, 0, 5}]
  • PARI
    a(n) = numbpart(7^n) \\ Michel Marcus, Oct 18 2014

Formula

a(n) = A000041(7^n). - Michel Marcus, Oct 18 2014

A327483 Triangle read by rows where T(n,k) is the number of integer partitions of 2^n with mean 2^k, 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 4, 1, 1, 22, 34, 8, 1, 1, 231, 919, 249, 16, 1, 1, 8349, 112540, 55974, 1906, 32, 1, 1, 1741630, 107608848, 161410965, 4602893, 14905, 64, 1, 1, 4351078600, 1949696350591, 12623411092535, 676491536028, 461346215, 117874, 128, 1
Offset: 0

Views

Author

Gus Wiseman, Sep 13 2019

Keywords

Comments

T(n,k) is the number of partitions of 2^n into 2^(n-k) parts. - Chai Wah Wu, Sep 21 2023

Examples

			Triangle begins:
      1
      1       1
      1       2         1
      1       5         4         1
      1      22        34         8       1
      1     231       919       249      16     1
      1    8349    112540     55974    1906    32  1
      1 1741630 107608848 161410965 4602893 14905 64 1
      ...
		

Crossrefs

Row sums are A327484.
Column k = 1 is A068413 (shifted once to the right).

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[2^n],Mean[#]==2^k&]],{n,0,5},{k,0,n}]
  • Python
    from sympy.utilities.iterables import partitions
    from sympy import npartitions
    def A327483_T(n,k):
        if k == 0 or k == n: return 1
        if k == n-1: return 1<Chai Wah Wu, Sep 21 2023
    
  • Python
    # uses A008284_T
    def A327483_T(n,k): return A008284_T(1<Chai Wah Wu, Sep 21 2023

Formula

T(n+1,n) = 2^n for n >= 0. - Chai Wah Wu, Sep 14 2019

Extensions

a(28)-a(35) from Chai Wah Wu, Sep 14 2019
Row n=8 from Alois P. Heinz, Sep 21 2023

A327484 Number of integer partitions of 2^n whose mean is a power of 2.

Original entry on oeis.org

1, 2, 4, 11, 66, 1417, 178803, 275379307, 15254411521973, 108800468645440803267, 964567296140908420613296779144, 219614169629364529542990295052656098001967511, 38626966436500261962963100479469496821891576834974275502742922521
Offset: 0

Views

Author

Gus Wiseman, Sep 13 2019

Keywords

Comments

Number of partitions of 2^n whose number of parts is a power of 2. - Chai Wah Wu, Sep 21 2023

Examples

			The a(0) = 1 through a(3) = 11 partitions:
  (1)  (2)   (4)     (8)
       (11)  (22)    (44)
             (31)    (53)
             (1111)  (62)
                     (71)
                     (2222)
                     (3221)
                     (3311)
                     (4211)
                     (5111)
                     (11111111)
		

Crossrefs

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[2^n],IntegerQ[Mean[#]]&]],{n,0,5}]
  • Python
    from sympy.utilities.iterables import partitions
    def A327484(n): return sum(1 for s,p in partitions(1<Chai Wah Wu, Sep 21 2023
    
  • Python
    # uses A008284_T
    def A327484(n): return sum(A008284_T(1<Chai Wah Wu, Sep 21 2023

Extensions

a(7) from Chai Wah Wu, Sep 14 2019
a(8)-a(11) from Alois P. Heinz, Sep 21 2023
a(12) from Chai Wah Wu, Sep 21 2023

A347615 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,k) is the number of partitions of n^k.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 5, 3, 1, 1, 1, 22, 30, 5, 1, 1, 1, 231, 3010, 231, 7, 1, 1, 1, 8349, 18004327, 1741630, 1958, 11, 1, 1, 1, 1741630, 133978259344888, 365749566870782, 3163127352, 17977, 15, 1, 1, 1, 4351078600, 233202632378520643600875145, 61847822068260244309086870983975, 1606903190858354689128371, 15285151248481, 173525, 22, 1
Offset: 0

Views

Author

Seiichi Manyama, Sep 08 2021

Keywords

Examples

			Square array begins:
  1, 1,   1,       1,               1, ...
  1, 1,   1,       1,               1, ...
  1, 2,   5,      22,             231, ...
  1, 3,  30,    3010,        18004327, ...
  1, 5, 231, 1741630, 365749566870782, ...
		

Crossrefs

Columns k=0..3 give A000012, A000041, A072213, A128854.
Rows n=0+1, 2-10 give A000012, A068413, A248728, A068413(2*n), A248730, A248732, A248734, A068413(3*n), A248728(2*n), A070177.
Main diagonal gives A347607.

Programs

  • PARI
    T(n, k) = numbpart(n^k);

Formula

T(n,k) = A000041(n^k).
Showing 1-10 of 13 results. Next