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.

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A083282 a(n) = n^(3*n).

Original entry on oeis.org

1, 64, 19683, 16777216, 30517578125, 101559956668416, 558545864083284007, 4722366482869645213696, 58149737003040059690390169, 1000000000000000000000000000000, 23225154419887808141001767796309131
Offset: 1

Views

Author

Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Jun 02 2003

Keywords

Comments

If sequence A000312 is used as the domain in the function f(n)=n^3, this sequence would be the resulting range. Also the range of the function f(n)=n^1.5 when sequence A062207 is used as the domain.

Crossrefs

Programs

  • Magma
    [n^(3*n): n in [1..30]]; // G. C. Greubel, Nov 01 2022
    
  • Mathematica
    Table[n^(3*n), {n, 30}] (* G. C. Greubel, Nov 01 2022 *)
  • SageMath
    [n^(3*n) for n in range(1,31)] # G. C. Greubel, Nov 01 2022

Formula

a(n) = A089072(3*n, n). - G. C. Greubel, Nov 01 2022

Extensions

More terms from Michael Joseph Halm, May 16 2004

A085741 a(n) = T(n)^n, where T() are the triangular numbers (A000217).

Original entry on oeis.org

1, 1, 9, 216, 10000, 759375, 85766121, 13492928512, 2821109907456, 756680642578125, 253295162119140625, 103510234140112521216, 50714860157241037295616, 29345269354638035222576971
Offset: 0

Views

Author

Jon Perry, Jul 21 2003

Keywords

Examples

			a(3) = T(3)^3 = 6^3 = 216.
		

Crossrefs

Cf. A000217.
Essentially the same as A061718.

Programs

  • Magma
    [((n*(n+1))/2)^n: n in [0..20]]; // Vincenzo Librandi, Sep 14 2011
  • Maple
    a:=n->mul(sum(j, j=1..n),k=1..n): seq(a(n), n=0..13); # Zerinvary Lajos, Jun 02 2007
  • Mathematica
    With[{rnn=Range[20]},Join[{1},First[#]^Last[#]&/@Thread[ {Accumulate[ rnn],  rnn}]]] (* Harvey P. Dale, Dec 08 2013 *)
  • PARI
    a(n) = (n*(n+1)/2)^n; \\ Michel Marcus, Feb 19 2019
    

Formula

a(n) = ((n*(n+1))/2)^n. - Vincenzo Librandi, Sep 14 2011

Extensions

More terms from Ray Chandler, Nov 09 2003

A212333 n-th power of the n-th pentagonal number.

Original entry on oeis.org

1, 1, 25, 1728, 234256, 52521875, 17596287801, 8235430000000, 5132188731375616, 4108400332687853397, 4108469075197275390625, 5019255990031848807858176, 7355827511386641000000000000, 12736801848653359358345383963927, 25724477018923486959881583081626689
Offset: 0

Views

Author

Bruno Berselli, May 09 2012

Keywords

Crossrefs

Programs

  • Magma
    [(n*(3*n-1)/2)^n: n in [0..14]];
  • Mathematica
    Join[{1}, Table[(n ((3 n - 1)/2))^n, {n, 14}]]

Formula

a(n) = A000326(n)^n.

A086648 Decimal expansion of the sum n^(-2n) for n=1 through infinity.

Original entry on oeis.org

1, 0, 6, 3, 8, 8, 7, 1, 0, 3, 7, 6, 2, 4, 1, 7, 0, 1, 1, 7, 4, 6, 4, 9, 1, 1, 1, 7, 6, 6, 0, 0, 1, 1, 1, 1, 5, 7, 2, 7, 1, 9, 9, 0, 7, 6, 8, 9, 1, 5, 9, 9, 2, 8, 6, 6, 3, 4, 0, 8, 3, 8, 6, 9, 6, 6, 7, 9, 4, 6, 6, 5, 5, 0, 7, 6, 0, 6, 5, 7, 3, 2, 5, 5, 5, 6, 2, 0, 8, 9, 0, 6, 9, 1, 9, 8, 7, 5, 1, 9, 4, 0, 2, 6, 6
Offset: 1

Views

Author

Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Jul 26 2003

Keywords

Comments

This number is the sum of the inverses of the terms in the sequence A062206.

Examples

			1.063887103762417011746491117660011115727199076891599286634083869667...
		

Crossrefs

Programs

Extensions

Clarified definition - R. J. Mathar, Feb 06 2009
More terms from Franklin T. Adams-Watters, Mar 23 2010

A155957 a(n) = (2*n^2)^n.

Original entry on oeis.org

1, 2, 64, 5832, 1048576, 312500000, 139314069504, 86812553324672, 72057594037927936, 76848453272063549952, 102400000000000000000000, 166712830744247830760081408, 325619086145088897570576531456
Offset: 0

Views

Author

Reinhard Zumkeller, Jan 31 2009

Keywords

Comments

Central terms of the triangle in A155955;

Crossrefs

Programs

  • Magma
    [(2*n^2)^n: n in [0..30]]; // G. C. Greubel, Sep 14 2018
  • Mathematica
    Table[If[n==0,1,(2*n^2)^n], {n, 0, 30}] (* G. C. Greubel, Sep 14 2018 *)
  • PARI
    vector(30, n, n--; (2*n^2)^n) \\ G. C. Greubel, Sep 14 2018
    

Formula

a(n) = A062206(n)*A000079(n).
a(n) = n! * [x^n] 1/(1 + LambertW(-2*n*x)). - Ilya Gutkovskiy, Oct 03 2017

A117812 a(n) = n^(2*n) - 1.

Original entry on oeis.org

0, 0, 15, 728, 65535, 9765624, 2176782335, 678223072848, 281474976710655, 150094635296999120, 99999999999999999999, 81402749386839761113320, 79496847203390844133441535, 91733330193268616658399616008, 123476695691247935826229781856255
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 17 2006

Keywords

Comments

a(n) = A048861(n)*A014566(n) = A062206(n) - 1.

Crossrefs

Programs

A233203 a(n) = floor(n^n / 2^n).

Original entry on oeis.org

1, 0, 1, 3, 16, 97, 729, 6433, 65536, 756680, 9765625, 139312339, 2176782336, 36972058910, 678223072849, 13363461010158, 281474976710656, 6311342330065435, 150094635296999121, 3773536025353076151, 100000000000000000000, 2785962590401641140642, 81402749386839761113321
Offset: 0

Views

Author

Alex Ratushnyak, Dec 05 2013

Keywords

Examples

			a(5) = floor(5^5 / 2^5) = floor(3125 / 32) = 97.
		

Crossrefs

Cf. A000079, A000312, A178537 (n^n mod 2^n for odd n), A206344.
Bisection gives: A062206 (even part).

Programs

Formula

a(n) = floor((n/2)^n).

A290770 a(n) = Product_{k=1..n} k^(2*k).

Original entry on oeis.org

1, 1, 16, 11664, 764411904, 7464960000000000, 16249593066946560000000000, 11020848942410302096869949440000000000, 3102093199396597590886754340698424229232640000000000, 465607547420733489126893933985879279492195953053596584509440000000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 10 2017

Keywords

Crossrefs

Programs

  • Magma
    [1] cat [(&*[k^(2*k): k in [1..n]]): n in [1..10]]; // G. C. Greubel, Oct 14 2018
  • Mathematica
    Table[Product[k^(2 k), {k, 1, n}], {n, 0, 9}]
    Table[Hyperfactorial[n]^2, {n, 0, 9}]
    Table[n!^(2 n)/BarnesG[n + 1]^2, {n, 0, 9}]
  • PARI
    a(n) = prod(k=1, n, k^(2*k)) \\ Felix Fröhlich, Aug 10 2017
    

Formula

a(n) = A002109(n)^2.
a(n) = A185141(n)/A000178(n-1)^2 for n > 0.
a(n) = (n!)^(2*n)/G(n+1)^2, where G() is the Barnes G-function.
a(n) ~ A^2*exp(-n^2/2)*n^(n*(n+1))*n^(1/6), where A is the Glaisher-Kinkelin constant (A074962).

A350008 a(n) = Sum_{k=0..n} k^(2*k).

Original entry on oeis.org

1, 2, 18, 747, 66283, 9831908, 2186614244, 680409687093, 282155386397749, 150376790683396870, 100150376790683396870, 81502899763630444510191, 79578350103154474577951727, 91812908543371771132977567736
Offset: 0

Views

Author

Seiichi Manyama, Dec 08 2021

Keywords

Comments

Partial sums of A062206.

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[If[k == 0, 1, k^(2*k)], {k, 0, n}]; Array[a, 14, 0] (* Amiram Eldar, Dec 08 2021 *)
  • PARI
    a(n) = sum(k=0, n, k^(2*k));

Formula

a(n) ~ n^(2*n). - Vaclav Kotesovec, Dec 08 2021

A086815 a(n)=(n-1)*n^(2*n).

Original entry on oeis.org

0, 16, 1458, 196608, 39062500, 10883911680, 4069338437094, 1970324836974592, 1200757082375992968, 900000000000000000000, 814027493868397611133210, 874465319237299285467856896, 1100799962319223399900795392108
Offset: 1

Views

Author

Benoit Cloitre, Aug 06 2003

Keywords

Comments

(-1)*determinant of the 2n X 2n matrix M_(i,j)=j if (i+j) is multiple of n, M_(i,j)=i otherwise.

Examples

			For n=3 the matrix is : [1 2 1 1 5 1], [1 2 2 4 2 2], [3 3 3 3 3 6], [4 2 4 4 5 4], [1 5 5 4 5 5], [6 6 3 6 6 6]
		

Crossrefs

Cf. A062206.

Programs

  • Mathematica
    Table[(n-1)n^(2n),{n,20}] (* Harvey P. Dale, Jul 23 2013 *)
  • PARI
    a(n)=(n-1)*n^(2*n)
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