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.

A075363 Triangle read by rows, in which n-th row gives n smallest powers of n.

Original entry on oeis.org

1, 2, 4, 3, 9, 27, 4, 16, 64, 256, 5, 25, 125, 625, 3125, 6, 36, 216, 1296, 7776, 46656, 7, 49, 343, 2401, 16807, 117649, 823543, 8, 64, 512, 4096, 32768, 262144, 2097152, 16777216, 9, 81, 729, 6561, 59049, 531441, 4782969, 43046721, 387420489, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000, 10000000000
Offset: 1

Views

Author

Amarnath Murthy, Sep 20 2002

Keywords

Comments

T(n,k) is the number of sequences with repetition (k-tuples) of k (not necessarily different) elements taken from an n-set S. These sequences are also called "words of length k over the alphabet S". For sequences without repetition (partial permutations) cf. A068424. - Manfred Boergens, Jun 18 2023

Examples

			From _Felix Fröhlich_, Sep 15 2019: (Start)
Triangle begins:
   1;
   2,   4;
   3,   9,   27;
   4,  16,   64,   256;
   5,  25,  125,   625,   3125;
   6,  36,  216,  1296,   7776,   46656;
   7,  49,  343,  2401,  16807,  117649,  823543;
   8,  64,  512,  4096,  32768,  262144, 2097152, 16777216;
   9,  81,  729,  6561,  59049,  531441, 4782969, 43046721, 387420489; (End)
		

Crossrefs

T(n, 1) = A000027(n), T(n, n) = A000312(n). Cf. A090414.

Programs

  • Mathematica
    Array[#^Range[#] &, 10] (* Paolo Xausa, Jun 09 2025 *)
  • PARI
    row(n) = for(k=1, n, print1(n^k, ", "))
    trianglerows(n) = for(x=1, n, row(x); print(""))
    /* Print initial 10 rows as follows: */
    trianglerows(10) \\ Felix Fröhlich, Sep 15 2019
    
  • Python
    from math import isqrt, comb
    def A075363(n): return (isqrt(n<<3)+1>>1)**(n-comb((m:=isqrt(k:=n<<1))+(k>m*(m+1)),2)) # Chai Wah Wu, Jun 08 2025

Formula

T(n, k) = n^k, 1<=k<=n.
a(n) = A002024(n)^A002260(n). [Gerald Hillier, Feb 12 2009]

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 20 2003
More terms from Michel Marcus, Sep 15 2019

A190343 a(n) = floor(n^((n-1)/2)).

Original entry on oeis.org

1, 1, 3, 8, 25, 88, 343, 1448, 6561, 31622, 161051, 861979, 4826809, 28172943, 170859375, 1073741824, 6975757441, 46753733110, 322687697779, 2289733608959, 16679880978201, 124577080440588, 952809757913927, 7454684703958210, 59604644775390625, 486594112179717592
Offset: 1

Views

Author

Bruno Berselli, May 12 2011

Keywords

Examples

			a(6) = 88 = floor(6^(5/2)).
		

Crossrefs

Programs

  • Magma
    [Floor(n^((n-1)/2)): n in [1..24]];
    
  • Mathematica
    Table[Floor[n^((n - 1)/2)], {n, 40}] (* Vincenzo Librandi, Mar 26 2013 *)
  • PARI
    for(n=1,20, print1(floor(n^((n-1)/2)), ", ")) \\ G. C. Greubel, Dec 30 2017
    
  • Python
    from math import isqrt
    def A190343(n): return isqrt(n**(n-1)) # Chai Wah Wu, Jun 08 2025

A147771 a(n) = round(n^(n/2)).

Original entry on oeis.org

1, 2, 5, 16, 56, 216, 907, 4096, 19683, 100000, 534146, 2985984, 17403307, 105413504, 661735514, 4294967296, 28761784748, 198359290368, 1406563064942, 10240000000000, 76436817165460, 584318301411328, 4569515072723572
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    lst={};Do[AppendTo[lst,Round[(n^n)^(1/2)]],{n,40}];lst
    Table[Round[n^(n/2)],{n,30}] (* Harvey P. Dale, Feb 17 2020 *)
  • Python
    from gmpy2 import isqrt_rem
    def A147771(n):
        i, j = isqrt_rem(n**n)
        return int(i+int(4*(j-i) >= 1)) # Chai Wah Wu, Aug 16 2016
Showing 1-3 of 3 results.