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.

A204452 A014330 - A203577. Difference between the exponential convolution of A000108 (Catalan) with itself and the corresponding exponential half-convolution.

Original entry on oeis.org

0, 1, 2, 11, 34, 212, 804, 5567, 24014, 178148, 839596, 6501420, 32658872, 259775440, 1368965576, 11080668871, 60613092662, 496461841956, 2798385807012, 23113333523180, 133539494791000, 1109722749130576, 6545965568001272
Offset: 0

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Author

Wolfdieter Lang, Jan 16 2012

Keywords

Comments

For the exponential (also known as binomial) half-convolution of the Catalan sequence A000108 with itself see A203577.

Examples

			With A000108 = {1, 1, 2, 5, 14, 42,...}
  a(4) = 4*5*1 + 1*14*1 = 34.
  a(5) = 10*5*2 + 5*14*1 + 1*42*1 = 212.
		

Crossrefs

Programs

Formula

a(n) = sum(binomial(n,k)*C(k)*C(n-k),k=floor(n/2)+1..n), n>=0, with C(n)=A000108(n), the Catalan numbers.
E.g.f.: (C(x)^2 - C2(x^2))/2 with the e.g.f. C(x) of A000108, and the o.g.f. C2(x) of the sequence {(C(n)/n!)^2}. Compare this with the e.g.f. of A203577.
C(x) = hypergeom([1/2],[2],4*x) (see the e.g.f. of A000108 for the version involving BesselI functions), and
C2(x) = hypergeom([1/2,1/2],[1,2,2],16*x).

A014333 Three-fold exponential convolution of Catalan numbers with themselves.

Original entry on oeis.org

1, 3, 12, 57, 306, 1806, 11508, 78147, 559962, 4201038, 32792472, 264946446, 2206077804, 18860908644, 165050642736, 1474389557739, 13413397423482, 124030117316238, 1163661348170328, 11060842687616610, 106377560784576612, 1034009073326130876
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    m:=40;
    R:=PowerSeriesRing(Rationals(), m);
    f:= func< x | (&+[(k+1-x)*x^(2*k)/(Factorial(k)*Factorial(k+1)): k in [0..m+2]]) >;
    Coefficients(R!(Laplace( Exp(6*x)*( f(x) )^3 ))); // G. C. Greubel, Jan 06 2023
    
  • Mathematica
    nmax = 20; CoefficientList[Series[E^(6*x)*(BesselI[0, 2*x] - BesselI[1, 2*x])^3, {x, 0, nmax}], x] * Range[0, nmax]! (* Vaclav Kotesovec, Nov 13 2017 *)
  • SageMath
    m=40
    def f(x): return sum((k+1-x)*x^(2*k)/(factorial(k)*factorial(k+1)) for k in range(m+2))
    def A014333_list(prec):
        P. = PowerSeriesRing(QQ, prec)
        return P( exp(6*x)*( f(x) )^3 ).egf_to_ogf().list()
    A014333_list(m) # G. C. Greubel, Jan 06 2023

Formula

E.g.f.: exp(6*x)*(BesselI(0,2*x) - BesselI(1,2*x))^3. - Ilya Gutkovskiy, Nov 01 2017
From Vaclav Kotesovec, Nov 13 2017: (Start)
Recurrence: (n+1)*(n+2)*(n+3)*a(n) = 4*(6*n^3 + 13*n^2 + 2*n - 3)*a(n-1) - 4*(n-1)*(44*n^2 - 16*n - 21)*a(n-2) + 192*(n-2)*(n-1)*(2*n - 3)*a(n-3).
a(n) ~ 2^(2*n) * 3^(n + 9/2) / (Pi^(3/2) * n^(9/2)). (End)

A203577 Exponential (or binomial) half-convolution of the sequence A000108 (Catalan) with itself.

Original entry on oeis.org

1, 1, 4, 11, 58, 212, 1304, 5567, 37734, 178148, 1284124, 6501420, 48758648, 259775440, 2000594288, 11080668871, 86930955662, 496461841956, 3947716126292, 23113333523180, 185660199980696, 1109722749130576, 8983793097101144, 54645629076275356, 445109373450545608, 2748480598104423952
Offset: 0

Views

Author

Wolfdieter Lang, Jan 13 2012

Keywords

Comments

For the definition of the exponential (also known as binomial) half-convolution of a sequence with itself see A203576, where also the rule for the e.g.f. is given.

Examples

			With Catalan = A000108 = {1, 1, 2, 5, 14, 42, ...}
a(4) = 1*1*14 + 4*1*5 + 6*2*2 = 58.
a(5) = 1*1*42 + 5*1*14 + 10*2*5 = 212.
		

Crossrefs

Cf. A203576, A000108, A014330 (exponential convolution).

Programs

  • Mathematica
    a[n_] := Sum[ Binomial[n, k]*CatalanNumber[k]*CatalanNumber[n - k], {k, 0, n/2}]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Jun 21 2013 *)
  • PARI
    hat(b,n) = sum(k=0,n\2,binomial(n,k)*b(k)*b(n-k))
    A203577(n)=hat(A000108,n)  \\ where A000108(n)=(2*n)!/n!/(n+1)! \\ - M. F. Hasler, Jan 13 2012

Formula

a(n) = Sum_{k=0..floor(n/2)} binomial(n,k)*Catalan(k)*Catalan(n-k), n >= 0.
E.g.f.: (C(x)^2 + C2(x^2))/2 with the e.g.f. C(x) of A000108, and the e.g.f. C2(x) := Sum_{n>=0} Catalan(n)^2*x^n/(n!)^2 of the scaled Catalan squares. See a comment above.
C(x) = hypergeom([1/2],[2],4*x) (see A000108 for the version involving BesselI functions), and
C2(x) = hypergeom([1/2,1/2],[1,2,2],16*x).
Recurrence: n*(n+1)^2 * (n+2)^2 * (3*n^6 - 39*n^5 + 166*n^4 - 322*n^3 + 316*n^2 - 153*n + 27)*a(n) = 12*(n-1)*n*(n+1)^2 * (3*n^7 - 34*n^6 + 113*n^5 - 121*n^4 - 19*n^3 + 68*n^2 + 17*n - 18)*a(n-1) + 32*(3*n^11 - 45*n^10 + 220*n^9 - 448*n^8 + 173*n^7 + 920*n^6 - 1696*n^5 + 842*n^4 + 580*n^3 - 846*n^2 + 360*n - 54)*a(n-2) - 768*(n-2)^3 * n *(3*n^7 - 34*n^6 + 113*n^5 - 121*n^4 - 19*n^3 + 68*n^2 + 17*n - 18)*a(n-3) + 2048*(n-3)^3 * (n-2)^2 * (3*n^6 - 21*n^5 + 16*n^4 + 12*n^3 + n^2 - 2)*a(n-4). - Vaclav Kotesovec, Feb 25 2014
a(n) ~ 2^(3*n+2)/(Pi*n^3) * (1 + (1+(-1)^n)/sqrt(2*Pi*n)). - Vaclav Kotesovec, Feb 25 2014

A277220 Exponential convolution of Fibonacci (A000045) and Catalan (A000108) numbers.

Original entry on oeis.org

0, 1, 3, 11, 43, 180, 790, 3590, 16745, 79705, 385615, 1890747, 9375216, 46931897, 236873261, 1204089630, 6159064015, 31678706490, 163739008070, 850051218980, 4430529313065, 23175017046351, 121617754070653, 640122809255716, 3378402106118508, 17875011275340275
Offset: 0

Views

Author

Vladimir Reshetnikov, Oct 06 2016

Keywords

Crossrefs

Programs

  • Magma
    [(&+[Binomial(n,k)*Fibonacci(k)*Catalan(n-k): k in [0..n]]): n in [0..30]]; // G. C. Greubel, Oct 22 2018
  • Mathematica
    Table[Sum[Binomial[n, k] Fibonacci[k] CatalanNumber[n - k], {k, 0, n}], {n, 0, 30}] (* or *)
    Round@Table[(GoldenRatio^n Hypergeometric2F1[1/2, -n, 2, -4/GoldenRatio] - (-GoldenRatio)^(-n) Hypergeometric2F1[1/2, -n, 2, 4 GoldenRatio])/Sqrt[5], {n, 0, 30}] (* Round is equivalent to FullSimplify here, but is much faster *)
  • PARI
    for(n=0, 30, print1(sum(k=0,n, binomial(n,k)*fibonacci(k)* binomial(2*n-2*k,n-k)/(n-k+1)), ", ")) \\ G. C. Greubel, Oct 22 2018
    

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * A000045(k) * A000108(n-k).
a(n) = (phi^n * hypergeom([1/2, -n], [2], -4/phi) - (-phi)^(-n) * hypergeom([1/2, -n], [2], 4*phi))/sqrt(5), where phi = (1+sqrt(5))/2 = A001622.
Recurrence: 19*(n+1)*(n+2)*(11*n+13)*a(n) + 2*(55*n^3+208*n^2+311*n+230)*a(n+1) + 2*(55*n^3+373*n^2+674*n+206)*a(n+3) = (n+2)*(297*n^2+1022*n+617)*a(n+2) + (n+3)*(n+5)*(11*n+2)*a(n+4).
E.g.f.: 2*exp(5*x/2)*sinh(x*sqrt(5)/2)*(BesselI_0(2*x) - BesselI_1(2*x))/sqrt(5) (the product of e.g.f. for Fibonacci and Catalan numbers).
a(n) ~ (phi + 4)^(n + 3/2) / (8 * sqrt(5*Pi) * n^(3/2)), where phi = A001622 = (1 + sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Mar 10 2018

A294498 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of e.g.f. exp(2*k*x)*(BesselI(0,2*x) - BesselI(1,2*x))^k.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 6, 5, 0, 1, 4, 12, 22, 14, 0, 1, 5, 20, 57, 92, 42, 0, 1, 6, 30, 116, 306, 424, 132, 0, 1, 7, 42, 205, 752, 1806, 2108, 429, 0, 1, 8, 56, 330, 1550, 5328, 11508, 11134, 1430, 0, 1, 9, 72, 497, 2844, 12730, 40632, 78147, 61748, 4862, 0
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 01 2017

Keywords

Comments

A(n,k) is the k-fold exponential convolution of Catalan numbers with themselves, evaluated at n.

Examples

			E.g.f. of column k: A_k(x) = 1 + k*x/1! +  k*(k + 1)*x^2/2! + k*(k^2 + 3*k + 1)*x^3/3! + k^2*(k^2 + 6*k + 7)*x^4/4! + k*(k^4 + 10*k^3 + 25*k^2 + 10*k - 4)*x^5/5! + ...
Square array begins:
  1,   1,    1,     1,     1,      1,  ...
  0,   1,    2,     3,     4,      5,  ...
  0,   2,    6,    12,    20,     30,  ...
  0,   5,   22,    57,   116,    205,  ...
  0,  14,   92,   306,   752,   1550,  ...
  0,  42,  424,  1806,  5328,  12730,  ...
		

Crossrefs

Columns k=0..3 give A000007, A000108, A014330, A014333.
Rows n=0..2 give A000012, A001477, A002378.
Main diagonal gives A294511.

Programs

  • Maple
    C:= proc(n) option remember; binomial(2*n, n)/(n+1) end:
    A:= proc(n, k) option remember; `if`(k=0, `if`(n=0, 1, 0), `if`(k=1, C(n),
          (h-> add(binomial(n, j)*A(j, h)*A(n-j, k-h), j=0..n))(iquo(k, 2))))
        end:
    seq(seq(A(n, d-n), n=0..d), d=0..12);  # Alois P. Heinz, Jan 06 2023
  • Mathematica
    Table[Function[k, n! SeriesCoefficient[Exp[2 k x] (BesselI[0, 2 x] - BesselI[1, 2 x])^k, {x, 0, n}]][j - n], {j, 0, 11}, {n, 0, j}] // Flatten

Formula

E.g.f. of column k: exp(2*k*x)*(BesselI(0,2*x) - BesselI(1,2*x))^k.

A277251 Exponential convolution of Lucas (A000032) and Catalan (A000108) numbers.

Original entry on oeis.org

2, 3, 9, 29, 107, 430, 1840, 8230, 38015, 179873, 867079, 4242111, 21006358, 105072063, 530058079, 2693632580, 13775807415, 70847283680, 366167521240, 1900884870494, 9907318315587, 51822028122623, 271949090063769, 1431369293422604, 7554372307564282
Offset: 0

Views

Author

Vladimir Reshetnikov, Oct 06 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[n, k] LucasL[k] CatalanNumber[n - k], {k, 0, n}], {n, 0,
       30}] (* or *)
    Round@Table[GoldenRatio^n Hypergeometric2F1[1/2, -n, 2, -4/GoldenRatio] + (-GoldenRatio)^(-n) Hypergeometric2F1[1/2, -n, 2, 4 GoldenRatio], {n, 0, 30}] (* Round is equivalent to FullSimplify here, but is much faster *)

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * A000032(k) * A000108(n-k).
a(n) = phi^n * hypergeom([1/2, -n], [2], -4/phi) + (-phi)^(-n) * hypergeom([1/2, -n], [2], 4*phi), where phi = (1+sqrt(5))/2 = A001622.
Recurrence: 19*(n+1)*(n+2)*(11*n+13)*a(n) + 2*(55*n^3+208*n^2+311*n+230)*a(n+1) + 2*(55*n^3+373*n^2+674*n+206)*a(n+3) = (n+2)*(297*n^2+1022*n+617)*a(n+2) + (n+3)*(n+5)*(11*n+2)*a(n+4).
E.g.f.: 2*exp(5*x/2)*cosh(x*sqrt(5)/2)*(BesselI_0(2*x) - BesselI_1(2*x)) (the product of e.g.f. for Lucas and Catalan numbers).
a(n) ~ (phi + 4)^(n + 3/2) / (8 * sqrt(Pi) * n^(3/2)), where phi = A001622 = (1 + sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Mar 10 2018
Showing 1-6 of 6 results.