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 1-8 of 8 results.

A098803 a(n) = n^7 * 7^n.

Original entry on oeis.org

0, 7, 6272, 750141, 39337984, 1313046875, 32934190464, 678223072849, 12089663946752, 193010051319183, 2824752490000000, 38532504363714053, 495958345459089408, 6079641716636816419, 71493870602660352896
Offset: 0

Views

Author

Parthasarathy Nambi, Oct 05 2004

Keywords

Examples

			a(1) = 1^7 * 7^1 = 7.
a(2) = 2^7 * 7^2 = 6272.
		

Crossrefs

Programs

Formula

G.f.: 7*x*(117649*x^6 +2016840*x^5 +2859591*x^4 +828688*x^3 +58359*x^2 +840*x +1) / (7*x -1)^8. - Colin Barker, Apr 30 2013

Extensions

More terms from Stefan Steinerberger, Mar 06 2006
Offset changed from 1 to 0 by Vincenzo Librandi, Oct 27 2011

A062275 Array A(n, k) = n^k * k^n, n, k >= 0, read by antidiagonals.

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 3, 16, 3, 0, 0, 4, 72, 72, 4, 0, 0, 5, 256, 729, 256, 5, 0, 0, 6, 800, 5184, 5184, 800, 6, 0, 0, 7, 2304, 30375, 65536, 30375, 2304, 7, 0, 0, 8, 6272, 157464, 640000, 640000, 157464, 6272, 8, 0, 0, 9, 16384, 750141, 5308416, 9765625
Offset: 0

Views

Author

Henry Bottomley, Jul 02 2001

Keywords

Comments

Here 0^0 is defined to be 1. - Wolfdieter Lang, May 27 2018

Examples

			A(3, 2) = 3^2 * 2^3 = 9*8 = 72.
The array A(n, k) begins:
n\k 0 1   2   3    4     5      6      7       8        9       10 ...
0:  1 0   0   0    0     0      0      0       0        0        0 ...
1:  0 1   2   3    4     5      6      7       8        9       10 ...
2:  0 2  16  72  256   800   2304   6272   16384    41472   102400 ...
3:  0 3  72 729 5184 30375 157464 750141 3359232 14348907 59049000 ...
...
The triangle T(n, k) begins:
n\k  0  1    2      3      4      5      6    7  8  9 ...
0:   1
1:   0  0
2:   0  1    0
3:   0  2    2      0
4:   0  3   16      3      0
5:   0  4   72     72      4      0
6:   0  5  256    729    256      5      0
7:   0  6  800   5184   5184    800      6    0
8:   0  7 2304  30375  65536  30375   2304    7  0
9:   0  8 6272 157464 640000 640000 157464 6272  8  0
... - _Wolfdieter Lang_, May 22 2018
		

Crossrefs

Columns and rows of A, or columns and diagonals of T, include A000007, A001477, A007758, A062074, A062075 etc. Diagonals of A include A062206, A051443, A051490. Sum of rows of T are A062817(n), for n >= 1

Programs

  • Mathematica
    {{1}}~Join~Table[(#^k k^#) &[n - k], {n, 10}, {k, 0, n}] // Flatten (* Michael De Vlieger, May 24 2018 *)
  • PARI
    t1(n)=n-binomial(round(sqrt(2+2*n)), 2)
    t2(n)=binomial(floor(3/2+sqrt(2+2*n)), 2)-(n+1)
    a(n)=t1(n)^t2(n)*t2(n)^t1(n) \\ Eric Chen, Jun 09 2018

Formula

From Wolfdieter Lang, May 22 2018: (Start)
As a sequence: a(n) = A003992(n)*A004248(n).
As a triangle: T(n, k) = (n-k)^k * k^(n-k), for n >= 1 and k = 1..n. (End)

A146748 Numbers of the form n^k * k^n, where n,k > 1.

Original entry on oeis.org

16, 72, 256, 729, 800, 2304, 5184, 6272, 16384, 30375, 41472, 65536, 102400, 157464, 247808, 589824, 640000, 750141, 1384448, 3211264, 3359232, 5308416, 7372800, 9765625, 14348907, 16777216, 37879808, 39337984, 59049000, 84934656
Offset: 1

Views

Author

Howard Berman (howard_berman(AT)hotmail.com), Nov 01 2008

Keywords

Examples

			2^2 * 2^2 = 16,
2^3 * 3^2 = 72.
		

Crossrefs

Programs

  • Maple
    N:= 10^20: # for terms <= N
    S:= {}:
    for n from 2 to ilog2(N) do
      for k from n do
        v:= n^k * k^n;
        if v > N then break fi;
        S:= S union {v};
    od od:
    sort(convert(S,list)); # Robert Israel, Oct 31 2023

A198404 8^n*n^8.

Original entry on oeis.org

0, 8, 16384, 3359232, 268435456, 12800000000, 440301256704, 12089663946752, 281474976710656, 5777633090469888, 107374182400000000, 1841328767004311552, 29548117155177824256, 448452706436800053248, 6490588908866265677824, 90173697372979200000000
Offset: 0

Views

Author

Vincenzo Librandi, Oct 27 2011

Keywords

Crossrefs

Programs

  • Magma
    [8^n*n^8: n in [0..20]]
    
  • Mathematica
    Table[8^n n^8,{n,0,20}] (* or *) LinearRecurrence[{72,-2304,43008,-516096,4128768,-22020096,75497472,-150994944,134217728},{0,8,16384,3359232,268435456,12800000000,440301256704,12089663946752,281474976710656},20] (* Harvey P. Dale, Apr 28 2018 *)
  • PARI
    a(n)=8^n*n^8 \\ Charles R Greathouse IV, Jul 06 2017

Formula

G.f.: -8*x*(8*x +1)*(262144*x^6 +8060928*x^5 +16576512*x^4 +5924864*x^3 +259008*x^2 +1968*x +1) / (8*x -1)^9. - Colin Barker, Apr 30 2013

A198478 a(n) = 9^n * n^9.

Original entry on oeis.org

0, 9, 41472, 14348907, 1719926784, 115330078125, 5355700839936, 193010051319183, 5777633090469888, 150094635296999121, 3486784401000000000, 73994897046174912819, 1457274373159131021312, 26955214582765006137717
Offset: 0

Views

Author

Vincenzo Librandi, Oct 27 2011

Keywords

Crossrefs

Programs

  • Magma
    [9^n*n^9: n in [0..20]]
    
  • Mathematica
    Table[9^n*n^9, {n, 0, 20}] (* G. C. Greubel, May 17 2022 *)
  • SageMath
    [9^n*n^9 for n in (0..20)] # G. C. Greubel, May 17 2022

Formula

G.f.: 9*x*(1 + 4518*x + 1183248*x^2 + 64322586*x^3 + 1024762590*x^4 + 5210129466*x^5 + 7763290128*x^6 + 2401050438*x^7 + 43046721*x^8)/(1 - 9*x)^10. - Colin Barker, Apr 30 2013
a(n) = A001019(n)*A001017(n). - Michel Marcus, May 18 2022

A198479 a(n) = 10^n * n^10.

Original entry on oeis.org

0, 10, 102400, 59049000, 10485760000, 976562500000, 60466176000000, 2824752490000000, 107374182400000000, 3486784401000000000, 100000000000000000000, 2593742460100000000000, 61917364224000000000000
Offset: 0

Views

Author

Vincenzo Librandi, Oct 27 2011

Keywords

Crossrefs

Programs

  • Magma
    [10^n*n^10: n in [0..20]]
    
  • Mathematica
    Table[10^n*n^10, {n,0,20}] (* G. C. Greubel, May 17 2022 *)
  • SageMath
    [10^n*n^10 for n in (0..20)] # G. C. Greubel, May 17 2022

Formula

G.f.: 10*x*(1 + 10*x)*(1 + 10120*x + 4682800*x^2 + 408364000*x^3 + 9019900000*x^4 + 40836400000*x^5 + 46828000000*x^6 + 10120000000*x^7 + 100000000*x^8)/ (1-10*x)^11. - Colin Barker, May 01 2013
a(n) = A011557(n)*A008454(n). - Michel Marcus, May 18 2022

A198402 a(n) = 5^n * n^5.

Original entry on oeis.org

0, 5, 800, 30375, 640000, 9765625, 121500000, 1313046875, 12800000000, 115330078125, 976562500000, 7863818359375, 60750000000000, 453238525390625, 3282617187500000, 23174285888671875, 160000000000000000, 1083264923095703125
Offset: 0

Views

Author

Vincenzo Librandi, Oct 27 2011

Keywords

Crossrefs

Sequences of the form n^m*m^n: A001477 (m=1), A007758 (m=2), A062074 (m=3), A062075 (m=4), this sequence (m=5), A198403 (m=6), A098803 (m=7), A198404 (m=8), A198478 (m=9), A198479 (m=10), A098880 (m=11).

Programs

  • Magma
    [5^n*n^5: n in [0..20]]
    
  • Mathematica
    With[{m = 5}, Table[n^m*m^n, {n, 0, 30}]] (* G. C. Greubel, May 18 2022 *)
  • PARI
    a(n)=5^n*n^5 \\ Charles R Greathouse IV, Jul 06 2017
    
  • SageMath
    m=5; [n^m*m^n for n in (0..30)] # G. C. Greubel, May 18 2022

Formula

G.f.: 5*x*(1 + 130*x + 1650*x^2 + 3250*x^3 + 625*x^4)/(1-5*x)^6. - Colin Barker, Apr 30 2013
E.g.f.: 5*x*(1 + 75*x + 625*x^2 + 1250*x^3 + 625*x^4)*exp(5*x). - G. C. Greubel, May 18 2022
a(n) = A000351(n)*A000584(n). - Michel Marcus, May 19 2022

A198403 a(n) = 6^n * n^6.

Original entry on oeis.org

0, 6, 2304, 157464, 5308416, 121500000, 2176782336, 32934190464, 440301256704, 5355700839936, 60466176000000, 642717115324416, 6499837226778624, 63041475422674944, 590045794670739456, 5355700839936000000
Offset: 0

Views

Author

Vincenzo Librandi, Oct 27 2011

Keywords

Crossrefs

Sequences of the form n^m*m^n: A001477 (m=1), A007758 (m=2), A062074 (m=3), A062075 (m=4), A198402 (m=5), this sequence (m=6), A098803 (m=7), A198404 (m=8), A198478 (m=9), A198479 (m=10), A098880 (m=11).

Programs

Formula

G.f.: 6*x*(1 + 336*x + 8856*x^2 + 12096*x^3 + 1296*x^4)/(1-6*x)^7. - Colin Barker, Apr 30 2013
E.g.f.: 6*x*(1 + 186*x + 3240*x^2 + 14040*x^3 + 19440*x^4 + 7776*x^5)*exp(6*x). - G. C. Greubel, May 18 2022
a(n) = A000400(n)*A001014(n). - Michel Marcus, May 19 2022
a(n) = 42*a(n-1) - 756*a(n-2) + 7560*a(n-3) - 45360*a(n-4) + 163296*a(n-5) - 326592*a(n-6) + 279936*a(n-7). - Wesley Ivan Hurt, Sep 04 2022
Showing 1-8 of 8 results.