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.

Previous Showing 11-14 of 14 results.

A011846 a(n) = floor( binomial(n,9)/10 ).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 5, 22, 71, 200, 500, 1144, 2431, 4862, 9237, 16796, 29393, 49742, 81719, 130750, 204297, 312455, 468682, 690690, 1001500, 1430715, 2016007, 2804880, 3856710, 5245125, 7060746
Offset: 0

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Author

Keywords

Crossrefs

A column of triangle A011847.

Programs

Formula

a(n) = floor( binomial(n+1,10)/(n+1)). [Gary Detlefs, Nov 23 2011]

A095719 a(n) = Sum_{k = 0..floor(n/2)} floor(C(n-k,k)/(k+1)).

Original entry on oeis.org

1, 1, 2, 2, 4, 5, 8, 11, 18, 25, 40, 59, 90, 137, 210, 319, 492, 754, 1164, 1798, 2786, 4317, 6710, 10438, 16266, 25377, 39650, 62013, 97108, 152212, 238822, 375058, 589520, 927365, 1459960, 2300097, 3626211, 5720649, 9030450, 14263675
Offset: 1

Views

Author

Mike Zabrocki, Jul 08 2004

Keywords

Comments

Sums of diagonal entries in A011847.

Crossrefs

Programs

  • Magma
    A095719:= func< n | (&+[Floor(Binomial(n-k,k)/(k+1)): k in [0..Floor(n/2)]]) >;
    [A095719(n): n in [1..40]]; // G. C. Greubel, Oct 21 2024
    
  • Maple
    a:=n->add(floor(C(n-k,k)/(k+1)),k=0..n/2);
  • Mathematica
    Table[Sum[Floor[Binomial[n-k,k]/(k+1)],{k,0,n/2}],{n,40}] (* Harvey P. Dale, Apr 02 2019 *)
  • SageMath
    def A095719(n): return sum(binomial(n-k,k)//(k+1) for k in range(n//2+1))
    [A095719(n) for n in range(1,41)] # G. C. Greubel, Oct 21 2024

Formula

a(n) = Sum_{k=0..floor(n/2)} floor(C(n-k,k)/(k+1)).

A011843 a(n) = floor(binomial(n,5)/6).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 3, 9, 21, 42, 77, 132, 214, 333, 500, 728, 1031, 1428, 1938, 2584, 3391, 4389, 5608, 7084, 8855, 10963, 13455, 16380, 19792, 23751, 28318, 33562, 39556, 46376, 54105, 62832, 72649, 83657
Offset: 0

Views

Author

Keywords

Crossrefs

A column of triangle A011847.

Programs

  • Maple
    seq(floor(binomial(n,5)/6), n=0..38); # Zerinvary Lajos, Jan 12 2009

Formula

a(n) = +5*a(n-1) -10*a(n-2) +10*a(n-3) -5*a(n-4) +a(n-5) +a(n-18) -5*a(n-19) +10*a(n-20) -10*a(n-21) +5*a(n-22) -a(n-23) -a(n-36) +5*a(n-37) -10*a(n-38) +10*a(n-39) -5*a(n-40) +a(n-41) +a(n-54) -5*a(n-55) +10*a(n-56) -10*a(n-57) +5*a(n-58) -a(n-59). [R. J. Mathar, Apr 15 2010]
a(n) = floor(binomial(n+1,6)/(n+1)). [Gary Detlefs, Nov 23 2011]

A011844 a(n) = floor(C(n,7)/8).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 4, 15, 41, 99, 214, 429, 804, 1430, 2431, 3978, 6298, 9690, 14535, 21318, 30644, 43263, 60087, 82225, 111003, 148005, 195097, 254475, 328696, 420732, 534006, 672452, 840565, 1043460
Offset: 0

Views

Author

Keywords

Crossrefs

A column of triangle A011847.

Programs

  • Mathematica
    Floor[Binomial[Range[0,40],7]/8] (* Harvey P. Dale, Apr 23 2011 *)

Formula

a(n) = floor(binomial(n+1,8)/(n+1)). [Gary Detlefs, Nov 23 2011]
Previous Showing 11-14 of 14 results.