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 1-6 of 6 results.

A051036 a(n) = binomial(n, floor(n/4)).

Original entry on oeis.org

1, 1, 1, 1, 4, 5, 6, 7, 28, 36, 45, 55, 220, 286, 364, 455, 1820, 2380, 3060, 3876, 15504, 20349, 26334, 33649, 134596, 177100, 230230, 296010, 1184040, 1560780, 2035800, 2629575, 10518300, 13884156, 18156204, 23535820, 94143280, 124403620
Offset: 0

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Programs

A051033 a(n) = binomial(n, floor(n/3)).

Original entry on oeis.org

1, 1, 1, 3, 4, 5, 15, 21, 28, 84, 120, 165, 495, 715, 1001, 3003, 4368, 6188, 18564, 27132, 38760, 116280, 170544, 245157, 735471, 1081575, 1562275, 4686825, 6906900, 10015005, 30045015, 44352165, 64512240, 193536720, 286097760, 417225900, 1251677700
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Maple
    [seq(binomial(n,floor(n/3)), n=0..50)];
  • Mathematica
    a[n_] := Binomial[n, Floor[n/3]]; Array[a, 50, 0] (* Enrique Pérez Herrero, Mar 06 2012 *)

A051053 a(n) = binomial(n, floor(n/6)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 6, 7, 8, 9, 10, 11, 66, 78, 91, 105, 120, 136, 816, 969, 1140, 1330, 1540, 1771, 10626, 12650, 14950, 17550, 20475, 23751, 142506, 169911, 201376, 237336, 278256, 324632, 1947792, 2324784, 2760681, 3262623, 3838380, 4496388
Offset: 0

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Crossrefs

Programs

  • Maple
    seq(binomial(n, floor(n/6)), n=0..60); # Robert Israel, Mar 11 2018
  • Mathematica
    Table[Binomial[n,Floor[n/6]],{n,0,50}] (* Harvey P. Dale, Dec 18 2013 *)

Formula

From Robert Israel, Mar 11 2018: (Start)
Let n = 6*k+j, 0 <= j <= 5.
a(n+6)*(k+1)*Product_{m=1..5} (5*k+j+m) = a(n)*Product_{m=1..6} (6*k+j+m).
a(n) ~ sqrt(3/(5*Pi*k))*(6/5)^j*(6^6/5^5)^k as k -> infinity. (End)

A062947 a(n) = binomial(n,floor(n/7)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 7, 8, 9, 10, 11, 12, 13, 91, 105, 120, 136, 153, 171, 190, 1330, 1540, 1771, 2024, 2300, 2600, 2925, 20475, 23751, 27405, 31465, 35960, 40920, 46376, 324632, 376992, 435897, 501942, 575757, 658008, 749398, 5245786, 6096454, 7059052, 8145060
Offset: 0

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Author

Jason Earls, Jul 21 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Binomial[n,Floor[n/7]],{n,50}] (* Harvey P. Dale, Jul 24 2019 *)
  • PARI
    j=[]; for(n=1,75,j=concat(j,binomial(n,floor(n/7)))); j

Extensions

a(0)=1 prepended by Alois P. Heinz, Oct 20 2022

A066704 Triangle with a(n,k) = C(n,floor(n/k)) with n>=k>=1.

Original entry on oeis.org

1, 1, 2, 1, 3, 3, 1, 6, 4, 4, 1, 10, 5, 5, 5, 1, 20, 15, 6, 6, 6, 1, 35, 21, 7, 7, 7, 7, 1, 70, 28, 28, 8, 8, 8, 8, 1, 126, 84, 36, 9, 9, 9, 9, 9, 1, 252, 120, 45, 45, 10, 10, 10, 10, 10, 1, 462, 165, 55, 55, 11, 11, 11, 11, 11, 11, 1, 924, 495, 220, 66, 66, 12, 12, 12, 12, 12, 12
Offset: 1

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Author

Henry Bottomley, Jan 14 2002

Keywords

Examples

			Rows start:
  1;
  1,  2;
  1,  3, 3;
  1,  6, 4, 4;
  1, 10, 5, 5, 5;
  ...
		

Crossrefs

Row sums are A051054.
Columns include (most of) A000012, A001405, A051033, A051036, A051052, A051053, A062947 etc.
n appears A008619 times in the n-th row.
Cf. A060539.

A355703 a(n) = binomial(n, floor(log(n))).

Original entry on oeis.org

1, 1, 3, 4, 5, 6, 7, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 1330, 1540, 1771, 2024, 2300, 2600, 2925, 3276, 3654, 4060, 4495, 4960, 5456, 5984, 6545, 7140, 7770, 8436, 9139, 9880, 10660, 11480, 12341, 13244, 14190, 15180, 16215, 17296, 18424, 19600, 20825
Offset: 1

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Author

Christoph B. Kassir, Jul 14 2022

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> binomial(n, ilog(n)):
    seq(a(n), n=1..60);  # Alois P. Heinz, Jul 31 2022
  • Mathematica
    a[n_] := Binomial[n, Floor[Log[n]]]; Array[a, 50] (* Amiram Eldar, Jul 31 2022 *)
  • PARI
    a(n) = binomial(n, floor(log(n))); \\ Michel Marcus, Jul 31 2022
  • Python
    from numpy import log
    from math import comb, floor
    for n in range(1, 50):
        x = comb(n, floor(log(n)))
        print("{}, ".format(x), end='')
    
Showing 1-6 of 6 results.