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 1-7 of 7 results.

A253267 Decimal expansion of a constant related to A152686.

Original entry on oeis.org

1, 0, 9, 6, 4, 1, 4, 0, 7, 2, 5, 0, 7, 3, 2, 4, 4, 2, 3, 1, 1, 0, 2, 1, 5, 9, 9, 8, 8, 4, 4, 4, 4, 0, 3, 7, 5, 9, 4, 5, 9, 2, 9, 6, 0, 8, 7, 7, 7, 6, 9, 7, 9, 3, 8, 4, 6, 5, 0, 5, 6, 8, 1, 3, 7, 8, 0, 1, 4, 0, 5, 2, 1, 9, 3, 3, 3, 3, 6, 7, 0, 7, 3, 1, 2, 6, 9, 2, 8, 7, 5, 4, 6, 4, 1, 6, 9, 3, 7, 3, 9, 4, 1, 4, 4
Offset: 1

Views

Author

Vaclav Kotesovec, May 01 2015

Keywords

Examples

			1.0964140725073244231102159988444403759459296087776979384650568137801405219...
		

Crossrefs

Programs

  • Mathematica
    (* Iterations: *) Do[Print[N[Product[Product[Fibonacci[k],{k,1,j}],{j,1,n}] / (GoldenRatio^(n*(n+1)*(n+2)/6) * QPochhammer[-1/GoldenRatio^2]^n / 5^(n*(n+1)/4)),120]],{n,100,1000,100}]

Formula

Equals limit n->infinity A152686(n) / (((1+sqrt(5))/2)^(n*(n+1)*(n+2)/6) * A062073^n / 5^(n*(n+1)/4)).

A062381 Let A_n be the n X n matrix defined by A_n[i,j] = 1/F(i+j-1) for 1<=i,j<=n where F(k) is the k-th Fibonacci number (A000045). Then a_n = 1/det(A_n).

Original entry on oeis.org

1, -2, -360, 16848000, 1897448716800000, -3129723891582775706419200000, -541942196790147039091108680776954796441600000, 66373536294235576434745706427960099542896427384297349714149376000000
Offset: 1

Views

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 08 2001

Keywords

Comments

In the reference it is proved that not only det(A_n) is a reciprocal of an integer but the inverse matrix (A_n)^(-1) is an integer matrix.

Examples

			a(3) = -360 because the matrix is / 1,1,1/2 / 1,1/2, 1/3 / 1/2, 1/3, 1/5 / with determinant -1/360.
		

Crossrefs

Programs

  • Mathematica
    Table[(-1)^Floor[n/2]*Product[Fibonacci[k]^(n-Abs[k-n]),{k,1,2*n-1}],{n,1,10}]/Table[Product[Product[Fibonacci[k],{k,1,m-1}],{m,1,n}],{n,1,10}]^2 (* Alexander Adamchuk, May 18 2006 *)
  • PARI
    vector(8, n, 1/matdet(matrix(n, n, i, j, 1/fibonacci(i+j-1)))) \\ Colin Barker, May 01 2015

Formula

a(n) = s(n) * f(n) / h(n)^2, where s(n) = (-1)^Floor[n/2], f(n) = Product[Fibonacci[k]^(n-Abs[k-n]),{k,1,2*n-1}], h(n) = Product[Product[Fibonacci[k],{k,1,m-1}],{m,1,n}]. - Alexander Adamchuk, May 18 2006
a(n) ~ (-1)^floor(n/2) * A253270 * ((1+sqrt(5))/2)^(n*(2*n^2+1)/3) / (A253267^2 * 5^(n/2) * A062073^(2*n-2)). - Vaclav Kotesovec, May 01 2015

Extensions

More terms from Vladeta Jovovic, Jul 11 2001

A152687 Partial products operator applied thrice to nonzero Fibonacci numbers.

Original entry on oeis.org

1, 1, 2, 24, 8640, 746496000, 201231433728000000, 3554168771933456302080000000000, 139840535301953855934724122328694784000000000000000, 674129921807822677705190163721626103970522196466131271680000000000000000000000
Offset: 1

Views

Author

Keywords

Comments

Partial products of A152686.

Crossrefs

Programs

  • Mathematica
    Nest[FoldList[Times,#]&,Fibonacci[Range[10]],3] (* Harvey P. Dale, Oct 06 2017 *)
  • PARI
    a(n) = prod(i=1, n, prod(j=1, i, prod(k=1, j, fibonacci(k)))); \\ Michel Marcus, Sep 15 2018

Extensions

Edited by R. J. Mathar, Dec 12 2008
One more term (a(10)) from Harvey P. Dale, Oct 06 2017

A152690 Partial sums of superfactorials (A000178).

Original entry on oeis.org

1, 2, 4, 16, 304, 34864, 24918064, 125436246064, 5056710181206064, 1834938528961266006064, 6658608419043265483506006064, 265790273955000365854215115506006064
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    lst={};p0=1;s0=0;Do[p0*=a[n];s0+=p0;AppendTo[lst,s0],{n,0,4!}];lst
    s = 0; lst = {s}; Do[s += BarnesG[n]; AppendTo[lst, s], {n, 2, 13, 1}]; lst (* Zerinvary Lajos, Jul 16 2009 *)
    Table[Sum[BarnesG[k+1],{k,1,n}],{n,1,15}] (* Vaclav Kotesovec, Jul 10 2015 *)

Formula

G.f.: W(0)/(2-2*x) , where W(k) = 1 + 1/( 1 - x*(k+1)!/( x*(k+1)! + 1/W(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Aug 19 2013
a(n) ~ exp(1/12 - 3*n^2/4) * n^(n^2/2 - 1/12) * (2*Pi)^(n/2) / A, where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Jul 10 2015
a(n) = n! * G(n+1) + a(n-1), where G(z) is the Barnes G-function. - Daniel Suteu, Jul 23 2016

A253268 Product_{k=1..n} Fibonacci(k)^k.

Original entry on oeis.org

1, 1, 8, 648, 2025000, 530841600000, 33309523161907200000, 1259861409934788058133299200000, 76494996113757662751632456649087438028800000, 19375812441937279261781767910157290423127539712000000000000000
Offset: 1

Views

Author

Vaclav Kotesovec, May 01 2015

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Product[Fibonacci[k]^k,{k,1,n}],{n,1,10}]
    FoldList[Times,Table[Fibonacci[n]^n,{n,10}]] (* Harvey P. Dale, Oct 17 2019 *)

Formula

a(n) ~ c * ((1+sqrt(5))/2)^(n*(n+1)*(2*n+1)/6) / 5^(n*(n+1)/4), where c = A253270 = 1.1188674438617789501735355690557711005492672642422237428157122531318... .

A152688 Partial products of A152687.

Original entry on oeis.org

1, 1, 2, 48, 414720, 309586821120000, 62298599877271470735360000000000, 221419738218975714643056286355472083897548800000000000000000000, 30963454718960054822969246779894642673092903344400531870724683866888280945459200000000000000000000000000000000000
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    lst={};p0=p1=p2=p3=1;Do[p0*=a[n];p1*=p0;p2*=p1;p3*=p2;AppendTo[lst,p3],{n,1,2*3!}];lst

Extensions

Better definition from Omar E. Pol, Aug 06 2009

A265944 Absolute value of the determinant of the matrix whose terms are fibonacci(m+r+s)^(n) with 0 <= r, s <=n, for any m.

Original entry on oeis.org

1, 2, 36, 13824, 324000000, 1209323520000000, 1923567501916569600000000, 3436011282355888738787131392000000000, 18204541483393435808637499286914987185930240000000000, 753091424970084722185225494963366011108371967508480000000000000000000000
Offset: 1

Views

Author

Michel Marcus, Dec 23 2015

Keywords

Crossrefs

Programs

  • PARI
    a(n) = prod(j=0, n, binomial(n, j)) * prod(j=1,n, fibonacci(j)^(n-j+1))^2;

Formula

a(n) = (Product_{j=0..n} binomial(n,j)) * (Product_{j=1..n} fibonacci(j)^(n-j+1))^2.
a(n) = A001142(n)*A152686(n)^2.
Showing 1-7 of 7 results.