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 1-10 of 15 results. Next

A050870 T(h,k) = binomial(h,k) - A050186(h,k).

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 2, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 3, 2, 3, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 4, 0, 6, 0, 4, 0, 1, 1, 0, 0, 3, 0, 0, 3, 0, 0, 1, 1, 0, 5, 0, 10, 2, 10, 0, 5, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 6, 4, 15, 0, 24, 0, 15, 4, 6, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 7, 0, 21, 0, 35, 2, 35, 0, 21, 0, 7, 0, 1, 1, 0
Offset: 0

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Comments

T(h,k) = number of periodic binary words of k 1's and h-k 0's.

Examples

			0;
0,0;
1,0,1;
1,0,0,1;
1,0,2,0,1;
1,0,0,0,0,1;
1,0,3,2,3,0,1;
1,0,0,0,0,0,0,1;
1,0,4,0,6,0,4,0,1;
1,0,0,3,0,0,3,0,0,1;
1,0,5,0,10,2,10,0,5,0,1;
		

Crossrefs

Cf. A007318. Different from A053200.

Programs

  • Maple
    A050186 := proc(n,k)
            if n = 0 then
                    1;
            else
            add (numtheory[mobius](d)*binomial(n/d,k/d),d =numtheory[divisors](igcd(n,k))) ;
            end if;
    end proc:
    A050870 := proc(n,k)
            binomial(n,k)-A050186(n,k) ;
    end proc:
    seq(seq(A050870(n,k),k=0..n),n=0..20) ; # R. J. Mathar, Sep 24 2011
  • Mathematica
    T[n_, k_] := Binomial[n, k] - If[n == 0, 1, Sum[MoebiusMu[d] Binomial[n/d, k/d], {d, Divisors[GCD[n, k]]}]];
    Table[T[n, k], {n, 0, 15}, {k, 0, n}] (* Jean-François Alcover, Jul 01 2019 *)

Extensions

Edited by N. J. A. Sloane, Aug 29 2008

A050190 T(n,5), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 6, 21, 56, 126, 250, 462, 792, 1287, 2002, 3000, 4368, 6188, 8568, 11628, 15500, 20349, 26334, 33649, 42504, 53125, 65780, 80730, 98280, 118755, 142500, 169911, 201376, 237336, 278256, 324625, 376992, 435897, 501942
Offset: 5

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Crossrefs

Programs

  • Magma
    [n*floor(Binomial(n-1, 4)/5): n in [5..40]]; // G. C. Greubel, Nov 25 2017
    
  • Mathematica
    Table[n*Floor[Binomial[n - 1, 4]/5], {n, 5, 50}] (* G. C. Greubel, Nov 25 2017 *)
    Drop[CoefficientList[Series[(x^5*(3 + x^2 + x^3)*(2 - x + 2*x^2 + x^3 + x^4))/((1 - x)^4*(1 - x^5)^2), {x, 0, 50}], x], 4] (* G. C. Greubel, Nov 27 2017 *)
  • PARI
    for(n=5,40, print1(n*floor(binomial(n-1, 4)/5), ", ")) \\ G. C. Greubel, Nov 25 2017
    
  • PARI
    x='x+O('x^30); concat([0], Vec((x^5*(3 + x^2 + x^3)*(2 - x + 2*x^2 + x^3 + x^4))/((1 - x)^4*(1 - x^5)^2))) \\ G. C. Greubel, Nov 27 2017

Formula

a(n) = n * A051170(n).
From Ralf Stephan, Aug 18 2004: (Start)
G.f.: (x^5*(3 + x^2 + x^3)*(2 - x + 2*x^2 + x^3 + x^4))/((1 - x)^4*(1 - x^5)^2). (corrected by G. C. Greubel, Nov 27 2017)
a(n) = A000389(n) - [5 divides n]*n/5.
a(n) = n*floor(C(n-1, 4)/5). (End)
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + 2*a(n-5) - 8*a(n-6) + 12*a(n-7) - 8*a(n-8) + 2*a(n-9) - a(n-10) + 4*a(n-11) - 6*a(n-12) + 4*a(n-13) - a(n-14). - R. J. Mathar, May 20 2013

Extensions

More terms from Ralf Stephan, Aug 18 2004

A050188 T(n,3), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 4, 10, 18, 35, 56, 81, 120, 165, 216, 286, 364, 450, 560, 680, 810, 969, 1140, 1323, 1540, 1771, 2016, 2300, 2600, 2916, 3276, 3654, 4050, 4495, 4960, 5445, 5984, 6545, 7128, 7770, 8436, 9126, 9880, 10660, 11466, 12341, 13244, 14175
Offset: 3

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Crossrefs

T(n, 3)=n*A001840(n).

A050189 T(n,4), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 5, 12, 35, 64, 126, 200, 330, 480, 715, 980, 1365, 1792, 2380, 3024, 3876, 4800, 5985, 7260, 8855, 10560, 12650, 14872, 17550, 20384, 23751, 27300, 31465, 35840, 40920, 46240, 52360, 58752, 66045, 73644, 82251, 91200
Offset: 4

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Formula

Seems to be n * A006918.
From Chai Wah Wu, Jun 11 2016: (Start)
a(n) = 2*a(n-1) + 2*a(n-2) - 6*a(n-3) + 6*a(n-5) - 2*a(n-6) - 2*a(n-7) + a(n-8) for n > 11 (conjectured).
G.f.: x^5*(5 + 2*x + x^2)/((1 - x)^5*(1 + x)^3) (conjectured). (End)

A050191 T(n,6), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 7, 24, 81, 200, 462, 900, 1716, 2968, 4995, 7952, 12376, 18468, 27132, 38640, 54243, 74448, 100947, 134352, 177100, 229944, 295974, 376376, 475020, 593280, 736281, 905632, 1107513, 1344224, 1623160, 1946916
Offset: 6

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Formula

Seems to be n*A011796.

A051192 T(n,7), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 8, 36, 120, 330, 792, 1716, 3430, 6435, 11440, 19448, 31824, 50388, 77520, 116277, 170544, 245157, 346104, 480700, 657800, 888030, 1184036, 1560780, 2035800, 2629575, 3365856, 4272048, 5379616, 6724515, 8347680, 10295472
Offset: 7

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Formula

Seems to be n*A011797.

A051195 T(2n+2,n), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 4, 12, 56, 200, 792, 2968, 11440, 43632, 167960, 646184, 2496144, 9655984, 37442160, 145416240, 565722720, 2203937120, 8597496600, 33577908232, 131282408400, 513791254704, 2012616400080, 7890369761872, 30957699535776
Offset: 0

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Formula

C(2n+2, n)-[n even]*C(n+1, n/2). - Ralf Stephan, Mar 19 2004
Conjecture: -(n+2)*(n-1)*a(n) +2*(n+1)*(3*n-4)*a(n-1) +4*(-n^2+5*n-1)*a(n-2) -8*n*(3*n-4)*a(n-3) +16*(n-1)*(2*n-5)*a(n-4)=0. - R. J. Mathar, May 20 2013

A051196 T(2n+3,n), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 5, 21, 81, 330, 1287, 4995, 19448, 75582, 293895, 1144066, 4457400, 17383734, 67863915, 265182525, 1037157858, 4059928950, 15905368710, 62359142274, 244662670200, 960566918220, 3773655743715, 14833897694226, 58343356817424
Offset: 0

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A051197 T(2n+4,n), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 6, 24, 120, 480, 2002, 7952, 31824, 125760, 497420, 1960464, 7726160, 30418752, 119759850, 471424160, 1855967520, 7307828352, 28781143380, 113380093840, 446775310800, 1761038703424, 6943526580276, 27385654785504
Offset: 0

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A051198 T(2n+5,n), array T as in A050186; a count of aperiodic binary words.

Original entry on oeis.org

0, 7, 36, 165, 715, 3000, 12376, 50388, 203490, 817190, 3268750, 13037895, 51895935, 206253075, 818809200, 3247943125, 12875774670, 51021117810, 202112640600, 800472431850, 3169870830000, 12551759587422, 49699896548176
Offset: 0

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Showing 1-10 of 15 results. Next