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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A109815 n^2 followed by n^3 followed by n.

Original entry on oeis.org

1, 1, 1, 4, 8, 2, 9, 27, 3, 16, 64, 4, 25, 125, 5, 36, 216, 6, 49, 343, 7, 64, 512, 8, 81, 729, 9, 100, 1000, 10, 121, 1331, 11, 144, 1728, 12, 169, 2197, 13, 196, 2744, 14, 225, 3375, 15, 256, 4096, 16, 289, 4913, 17, 324, 5832, 18, 361, 6859, 19, 400, 8000, 20
Offset: 1

Views

Author

Mohammad K. Azarian, Aug 30 2005

Keywords

Crossrefs

Cf. A000463.
Cf. A010872.

Programs

  • Mathematica
    Table[{n^2,n^3,n},{n,20}]//Flatten (* or *) LinearRecurrence[{0,0,4,0,0,-6,0,0,4,0,0,-1},{1,1,1,4,8,2,9,27,3,16,64,4},60] (* Harvey P. Dale, May 26 2018 *)

Formula

G.f.: x*(1+x+x^2+4*x^4-2*x^5-x^6+x^7+x^8) / ( (x-1)^4*(1+x+x^2)^4 ). - R. J. Mathar, Mar 03 2014
a(n) = floor((n+2)/3)^((n mod 3)+1). - Luce ETIENNE, Mar 01 2018

A110005 n followed by n^2 followed by n^4 followed by n^3.

Original entry on oeis.org

1, 1, 1, 1, 2, 4, 16, 8, 3, 9, 81, 27, 4, 16, 256, 64, 5, 25, 625, 125, 6, 36, 1296, 216, 7, 49, 2401, 343, 8, 64, 4096, 512, 9, 81, 6561, 729, 10, 100, 10000, 1000, 11, 121, 14641, 1331, 12, 144, 20736, 1728, 13, 169, 28561, 2197, 14, 196, 38416, 2744, 15, 225
Offset: 1

Views

Author

Mohammad K. Azarian, Sep 02 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Table[{n,n^2,n^4,n^3},{n,20}]//Flatten (* Harvey P. Dale, Jan 12 2020 *)

Formula

G.f.: x*(-1 -x -x^2 -x^3 +3*x^4 +x^5 -11*x^6 -3*x^7 -3*x^8 +x^9 -11*x^10 +3*x^11 +x^12 -x^13 -x^14 +x^15) / ( (x-1)^5 *(1+x)^5 *(x^2+1)^5 ). - R. J. Mathar, Sep 10 2016
a(n) = floor((n+3)/4)^((-2*(n mod 4)^3 + 15*(n mod 4)^2 -25*(n mod 4) +18)/6). - Luce ETIENNE, Apr 07 2018

A126951 List of pairs: k followed by k^3.

Original entry on oeis.org

1, 1, 2, 8, 3, 27, 4, 64, 5, 125, 6, 216, 7, 343, 8, 512, 9, 729, 10, 1000, 11, 1331, 12, 1728, 13, 2197, 14, 2744, 15, 3375, 16, 4096, 17, 4913, 18, 5832, 19, 6859, 20, 8000, 21, 9261, 22, 10648, 23, 12167, 24, 13824, 25, 15625, 26, 17576, 27, 19683, 28, 21952
Offset: 1

Views

Author

Zak Seidov, Mar 18 2007

Keywords

Crossrefs

Programs

  • Magma
    &cat[ [ n, n^3 ]: n in [1..40] ]; // Vincenzo Librandi, Apr 21 2011
  • Mathematica
    Table[((((-1)^(n+1))+1)/4)(n+1)- ((((-1)^(n+1))-1)/16)n^3,{n,64}]
    Flatten[Table[{n,n^3},{n,30}]] (* or *) LinearRecurrence[{0,4,0,-6,0,4,0,-1},{1,1,2,8,3,27,4,64},60] (* Harvey P. Dale, Mar 11 2018 *)

Formula

a(n) = (n+1)/2 if n is odd, a(n) = (n/2)^3 otherwise;
a(n) = ((((-1)^(n+1))+1)/4)*(n+1) - ((((-1)^(n+1))-1)/16)*n^3;
g.f.: (x + x^2 - 2*x^3 + 4*x^4 + x^5 + x^6)/(1 - x^2)^4.

A158613 Expansion of (1 - 2*x^3 - x^4 - x^5 + x^6 + x^7 - x^8)/(1 - x^3)^3.

Original entry on oeis.org

1, 0, 0, 1, -1, -1, 1, -2, -4, 1, -3, -9, 1, -4, -16, 1, -5, -25, 1, -6, -36, 1, -7, -49, 1, -8, -64, 1, -9, -81, 1, -10, -100, 1, -11, -121, 1, -12, -144, 1, -13, -169, 1, -14, -196, 1, -15, -225, 1, -16, -256, 1, -17, -289, 1, -18, -324, 1, -19, -361, 1, -20, -400, 1, -21, -441
Offset: 0

Views

Author

Roger L. Bagula, Mar 22 2009

Keywords

Comments

The sequence is given by the successive triples (1, -m, -m^2) with m = 0, 1, 2, 3, ... - Bruno Berselli, Aug 23 2018

Examples

			As array:
1,   0,    0;
1,  -1,   -1;
1,  -2,   -4;
1,  -3,   -9;
1,  -4,  -16;
1,  -5,  -25;
1,  -6,  -36;
1,  -7,  -49;
1,  -8,  -64;
1,  -9,  -81;
1, -10, -100 etc.
		

Crossrefs

Programs

  • Magma
    &cat [[1,-n,-n^2]: n in [0..25]]; // Bruno Berselli, Aug 23 2018
  • Mathematica
    CoefficientList[Series[(1-2x^3-x^4-x^5+x^6+x^7-x^8)/(1-x^3)^3,{x,0,100}],x] (* or *) LinearRecurrence[{0,0,3,0,0,-3,0,0,1},{1,0,0,1,-1,-1,1,-2,-4},100] (* Harvey P. Dale, Nov 22 2021 *)

Formula

From Bruno Berselli, Aug 23 2018: (Start)
G.f.: (1 - 2*x^3 - x^4 - x^5 + x^6 + x^7 - x^8)/((1 - x)^3*(1 + x + x^2)^3).
a(n) = 3*a(n-3) - 3*a(n-6) + a(n-9) for n>8.
a(n) = -(-1)^((n+1) mod 3)*floor(n/3)^(n mod 3). (End)

Extensions

Edited, new name, and a(1)-a(2) added by Bruno Berselli, Aug 23 2018
Previous Showing 21-24 of 24 results.