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.

User: Volkan Yildiz

Volkan Yildiz's wiki page.

Volkan Yildiz has authored 4 sequences.

A192480 a(n) = n + A000108(n-1) for n > 1; a(0)=0, a(1)=1.

Original entry on oeis.org

0, 1, 3, 5, 9, 19, 48, 139, 437, 1439, 4872, 16807, 58798, 208025, 742914, 2674455, 9694861, 35357687, 129644808, 477638719, 1767263210, 6564120441, 24466267042, 91482563663, 343059613674, 1289904147349, 4861946401478, 18367353072179, 69533550916032
Offset: 0

Author

Volkan Yildiz, Jul 01 2011

Keywords

Comments

a(n) is the number of components of the n-th Catalan tree A_n.

Crossrefs

Cf. A000108.

Programs

  • Maple
    C := proc(n) binomial(2*n,n)/(n+1) ; end proc:
    A192480 := proc(n) if n <=1 then n; else n+C(n-1) ; end if; end proc:
    seq(A192480(n),n=0..40) ; # R. J. Mathar, Jul 13 2011
  • Mathematica
    CoefficientList[Series[(2*x^2*(2 - x) + (1 - x)^2*(1 - Sqrt[1 - 4*x]))/(2*(1 - x)^2), {x,0,50}], x] (* G. C. Greubel, Mar 28 2017 *)
  • PARI
    x='x+O('x^50); concat([0], Vec((2*x^2*(2-x)+(1-x)^2*(1-sqrt(1-4*x)))/(2*(1-x)^2))) \\ G. C. Greubel, Mar 28 2017

Formula

G.f.: (2*x^2*(2-x)+(1-x)^2*(1-sqrt(1-4*x)))/(2*(1-x)^2).
For large n, a(n) ~ (2^(2n) +n^2*sqrt(Pi*n)) / sqrt(Pi *n^3).
Conjecture: n*(3*n^2-16*n+19)*a(n) +(-15*n^3+95*n^2-188*n+120)*a(n-1) +2*(2*n-5)*(3*n^2-10*n+6)*a(n-2)=0. - R. J. Mathar, Jun 14 2016

A192481 a(n) = Sum_{i=1..n-1} (2^i*C(i)-a(i)) * (2^(n-i)*C(n-i)-a(n-i)), a(1)=1, where C(i)=A000108(i-1) are Catalan numbers.

Original entry on oeis.org

1, 1, 6, 29, 162, 978, 6156, 40061, 267338, 1819238, 12576692, 88079378, 623581332, 4455663876, 32090099352, 232711721757, 1697799727066, 12452943237342, 91774314536100, 679234371006982, 5046438870909244, 37623611703611452, 281391143518722728
Offset: 1

Author

Volkan Yildiz, Jul 01 2011

Keywords

Comments

a(n) is the number of rows with the value false in the truth tables of all bracketed m-implication, case (i), with n distinct variables.

Crossrefs

Programs

  • Maple
    C := proc(n) binomial(2*n,n)/(n+1) ; end proc:
    A192481 := proc(n) option remember; if n<=1 then n; else add( (2^i*C(i-1)-procname(i))*(2^(n-i)*C(n-i-1)-procname(n-i)), i=1..n-1) ; end if; end proc:
  • Mathematica
    CoefficientList[Series[(2 - Sqrt[1 - 8*x] - Sqrt[3 - 4*x - 2*Sqrt[1 - 8*x]])/2, {x,0,50}], x] (* G. C. Greubel, Feb 12 2017 *)
  • PARI
    x='x+O('x^50); Vec((2-sqrt(1-8*x)-sqrt(3-4*x-2*sqrt(1-8*x)))/2) \\ G. C. Greubel, Feb 12 2017

Formula

G.f.: (2 - sqrt(1-8*x) - sqrt(3 - 4*x - 2*sqrt(1-8*x)))/2.
For large n, a(n) is asymptotically (1-2/sqrt 10) * 2^(3n-2)/ sqrt(pi*n^3).
D-finite with recurrence 10*n*(n-1)*(n-2)*a(n) -(n-1)*(n-2)*(149*n-396)*a(n-1) +2*(n-2)*(244*n^2-1618*n+2517)*a(n-2) +4
*(76*n^3-696*n^2+2165*n-2289)*a(n-3) +16*(2*n-9)*(56*n^2-336*n+451)*a(n-4) -256*(n-5)*(2*n-9)*(2*n-11)*a(n-5)=0. - R. J. Mathar, Jun 19 2021

Extensions

a(0) removed from definition by Georg Fischer, Jun 19 2021

A192479 a(n) = 2^n*C(n-1) - A186997(n-1), where C(n) are the Catalan numbers (A000108).

Original entry on oeis.org

1, 3, 12, 61, 344, 2074, 13080, 85229, 569264, 3876766, 26817304, 187908802, 1330934032, 9513485076, 68539442800, 497178707325, 3628198048352, 26617955242806, 196205766112536, 1452410901340598, 10792613273706320
Offset: 1

Author

Volkan Yildiz, Jul 01 2011

Keywords

Comments

a(n) is the number of rows with the value true in the truth tables of all bracketed formulas with n distinct propositions connected by the binary connective of implication.

Crossrefs

Cf. A186997.

Programs

  • Maple
    C := proc(n) binomial(2*n,n)/(n+1) ;end proc:
    Yildf := proc(n) option remember; if n<=1 then 1; else add( (2^i*C(i-1)-procname(i))*procname(n-i),i=1..n-1) ; end if; end proc:
    A192479 := proc(n) 2^n*C(n-1)-Yildf(n) ; end proc:
    seq(A192479(n),n=1..30) ; # R. J. Mathar, Jul 13 2011
  • Mathematica
    a[1] = 1; a[n_] := 2^n*CatalanNumber[n-1] - Sum[Binomial[k, n-k-1]*Binomial[n+2*k-1, n+k-1]/(n+k), {k, 1, n-1}]; Table[a[n], {n, 1, 30}] (* Jean-François Alcover, Apr 02 2015 *)

Formula

a(n) = 2^n*C(n) - f(n), with f(n) = Sum_{i=1..n-1} (2^i*C(i)-f(i))*f(n-i), starting f(0)=f(1)=1, where C(i) = A000108(i-1).
G.f.: 1 - 1/A186997(x). - Vladimir Kruchinin, Feb 17 2013
a(n+1) = Sum_{k=1..n+1} (binomial(k,n-k+1)*binomial(n+2*k-1,k))/(n+k), a(1)=1. - Vladimir Kruchinin, May 15 2014

A192482 a(n) = 2^n*C(n-1)-y(n), where y(n) = Sum_{i=1..n-1} (2^i*C(i-1)-y(i))*(2^(n-i)*C(n-i-1)-y(n-i)), y(0)=0, y(1)=1 and where C(i) is the i-th Catalan number.

Original entry on oeis.org

1, 3, 10, 51, 286, 1710, 10740, 69763, 464822, 3159450, 21821516, 152708078, 1080452972, 7716009724, 55545950568, 402649640163, 2936600795174, 21532660592418, 158645924209500, 1173875395710458, 8719519396134596, 64995349923442628, 486020221692290392
Offset: 1

Author

Volkan Yildiz, Jul 01 2011

Keywords

Comments

The sequence a(n) for n>=1 is the number of rows with the value true in the truth tables of all bracketed formulas with n distinct variables connected by the binary connective of m-implication, case(i).

Crossrefs

Programs

  • Maple
    C:= n-> binomial(2*n, n)/(n+1):
    y:= proc(n) option remember;
          `if`(n<2, n, add((2^i    *C(i-1)  -y(i))*
                           (2^(n-i)*C(n-i-1)-y(n-i)), i=1..n-1))
        end:
    a:= n-> 2^n*C(n-1) -y(n):
    seq(a(n), n=1..30);  # Alois P. Heinz, Feb 06 2012
  • Mathematica
    c = CatalanNumber; y[n_] := y[n] = If[n<2, n, Sum[(2^i*c[i-1]-y[i])*(2^(n-i)*c[n-i-1] - y[n-i]), {i, 1, n-1}]]; a[n_] := 2^n*c[n-1]-y[n]; Table[ a[n], {n, 1, 30}] (* Jean-François Alcover, Feb 28 2017, after Alois P. Heinz *)

Formula

a(n) = 2^n*C(n-1)-y(n), where y(n) = Sum_{i=1..n-1} (2^i*C(i-1)-y(i))*(2^(n-i)*C(n-i-1)-y(n-i)), y(0)=0, y(1)=1 and C(i) is the i-th Catalan number.