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.

A026068 (d(n)-r(n))/5, where d = A026066 and r is the periodic sequence with fundamental period (0,3,1,0,1).

Original entry on oeis.org

21, 33, 49, 68, 90, 116, 145, 179, 217, 259, 306, 357, 414, 476, 543, 616, 694, 779, 870, 967, 1071, 1181, 1299, 1424, 1556, 1696, 1843, 1999, 2163, 2335, 2516, 2705, 2904, 3112, 3329, 3556, 3792, 4039, 4296, 4563, 4841, 5129, 5429, 5740, 6062, 6396, 6741
Offset: 7

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Author

Keywords

Crossrefs

Cf. A152892.

Programs

  • Mathematica
    LinearRecurrence[{3,-3,1,0,1,-3,3,-1},{21,33,49,68,90,116,145,179},60] (* Harvey P. Dale, Sep 10 2014 *)

Formula

a(n)=(n + 7)*(n^2 + 35*n + 90)/30 - 1/5*(1 + ( - 1/2 + 3/10*5^(1/2))*cos(2*n*Pi/5) + (1/5*2^(1/2)*(5 + 5^(1/2))^(1/2) + 1/10*2^(1/2)*(5 - 5^(1/2))^(1/2))*sin(2*n*Pi/5) + ( - 1/2 - 3/10*5^(1/2))*cos(4*n*Pi/5) + ( - 1/10*2^(1/2)*(5 + 5^(1/2))^(1/2) + 1/5*2^(1/2)*(5 - 5^(1/2))^(1/2))*sin(4*n*Pi/5)) - Richard Choulet, Dec 14 2008
a(n)= 3*a(n-1) -3*a(n-2) +a(n-3) +a(n-5) -3*a(n-6) +3*a(n-7) -a(n-8). G.f.: -x^7*(-21+30*x-13*x^2+x^3+20*x^5-29*x^6+11*x^7)/( (x^4+x^3+x^2+x+1) * (x-1)^4). - R. J. Mathar, Oct 05 2009

Extensions

Corrected by T. D. Noe, Dec 11 2006

A026067 a(n) = (d(n)-r(n))/2, where d = A026066 and r is the periodic sequence with fundamental period (1,0,0,0).

Original entry on oeis.org

52, 84, 123, 170, 225, 290, 364, 448, 542, 648, 765, 894, 1035, 1190, 1358, 1540, 1736, 1948, 2175, 2418, 2677, 2954, 3248, 3560, 3890, 4240, 4609, 4998, 5407, 5838, 6290, 6764, 7260, 7780, 8323, 8890, 9481, 10098, 10740, 11408, 12102, 12824, 13573, 14350, 15155, 15990, 16854
Offset: 7

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Author

Keywords

Crossrefs

Cf. A026066.

Formula

G.f.: x^7*( 52-72*x+27*x^2+x^3+74*x^5-28*x^6-52*x^4 ) / ( (1+x)*(x^2+1)*(x-1)^4 ). - R. J. Mathar, Jun 23 2013

A094415 Triangle T read by rows: dot product * .

Original entry on oeis.org

1, 4, 5, 10, 13, 13, 20, 26, 28, 26, 35, 45, 50, 50, 45, 56, 71, 80, 83, 80, 71, 84, 105, 119, 126, 126, 119, 105, 120, 148, 168, 180, 184, 180, 168, 148, 165, 201, 228, 246, 255, 255, 246, 228, 201, 220, 265, 300, 325, 340, 345, 340, 325, 300, 265, 286, 341
Offset: 0

Views

Author

Ralf Stephan, May 02 2004

Keywords

Examples

			Triangle begins as:
   1;
   4,  5;
  10, 13, 13;
  20, 26, 28, 26;
  35, 45, 50, 50, 45;
  56, 71, 80, 83, 80, 71;
		

Crossrefs

Half-diagonal is A050410.
Row sums are A000537.
See also A094414, A088003.

Programs

  • GAP
    Flat(List([0..12], n-> List([0..n], k-> (n+1)*((n+2)*(n+3) + 3*k*(n-k+1))/6 ))); # G. C. Greubel, Oct 30 2019
  • Magma
    [(n+1)*((n+2)*(n+3) + 3*k*(n-k+1))/6: k in [0..n], n in [0..12]]; // G. C. Greubel, Oct 30 2019
    
  • Maple
    seq(seq( (n+1)*((n+2)*(n+3) + 3*k*(n-k+1))/6 , k=0..n), n=0..12); # G. C. Greubel, Oct 30 2019
  • Mathematica
    Table[(n+1)*((n+2)*(n+3) + 3*k*(n-k+1))/6, {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Oct 30 2019 *)
  • PARI
    T(n,k) = (n+1)*((n+2)*(n+3) + 3*k*(n-k+1))/6;
    for(n=0,12, for(k=0,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Oct 30 2019
    
  • Sage
    [[(n+1)*((n+2)*(n+3) + 3*k*(n-k+1))/6 for k in (0..n)] for n in (0..12)] # G. C. Greubel, Oct 30 2019
    

Formula

T(n, k) = n*(n^2 + 3*n*(1+k) + 2 - 3*k^2)/6 for n >= 0, 0 <= k <= n.
Showing 1-3 of 3 results.