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 1-4 of 4 results.

A294373 Product of first n Bell numbers.

Original entry on oeis.org

1, 1, 2, 10, 150, 7800, 1583400, 1388641800, 5748977052000, 121573617718644000, 14099500314919737900000, 9567497928695086546803000000, 40313580569855830588349480391000000, 1114446238307803607782300144651734867000000
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 29 2017

Keywords

Crossrefs

Programs

  • Maple
    B:= map(combinat:-bell, [$0..19]):
    map(i -> convert(B[1..i],`*`),[$1..20]); # Robert Israel, Oct 29 2017
  • Mathematica
    Table[Product[BellB[k], {k, 0, n}], {n, 0, 15}]

Formula

log(a(n)) ~ n^2 * LambertW(n)/2 * (1 - 3/(2*LambertW(n)) + 3/(2*LambertW(n)^2) + 1/(4*LambertW(n)^3)). - Vaclav Kotesovec, Feb 26 2021

A342166 Product of first n Fubini numbers.

Original entry on oeis.org

1, 1, 3, 39, 2925, 1582425, 7410496275, 350464600333575, 191295845123076910125, 1355763582602823185129417625, 138623522325287867599380791765497875, 224935042709004795568466587349227029537282375, 6318777956744220129890735589019782971247629409914638125
Offset: 0

Views

Author

Vaclav Kotesovec, Mar 03 2021

Keywords

Crossrefs

Programs

  • Maple
    g:= proc(n) option remember; `if`(n=0, 1,
          add(g(n-j)*binomial(n, j), j=1..n))
        end:
    a:= proc(n) option remember; `if`(n=0, 1, a(n-1)*g(n)) end:
    seq(a(n), n=0..15);  # Alois P. Heinz, Mar 03 2021
  • Mathematica
    Table[Product[Sum[j!*StirlingS2[k, j], {j, 0, k}], {k, 1, n}], {n, 0, 12}]
    Table[Product[PolyLog[-k, 1/2]/2, {k, 1, n}], {n, 0, 12}]
    FoldList[Times, 1, Table[PolyLog[-n, 1/2]/2, {n, 1, 12}]]

Formula

a(n) = Product_{k=1..n} A000670(k).
a(n) ~ c * BarnesG(n+2) / (2^n * log(2)^(n*(n+3)/2)), where c = 0.960303470666951851619546415046950178638511457142008903473074598398282549...
a(n) ~ c * Pi^((n+1)/2) * n^(n^2/2 + n + 5/12) / (A * 2^((n-1)/2) * exp(3*n^2/4 + n - 1/12) * log(2)^(n*(n+3)/2)), where A is the Glaisher-Kinkelin constant A074962.

A342177 Product of first n Motzkin numbers.

Original entry on oeis.org

1, 1, 2, 8, 72, 1512, 77112, 9793224, 3163211352, 2641281478920, 5779123875876960, 33507360232334614080, 519732664563742198994880, 21743016022024154894950804800, 2470745882646692817332839752643200, 767344490265348681664694707657903910400
Offset: 0

Views

Author

Vaclav Kotesovec, Mar 04 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n<2, 1,
          ((2*n+1)*b(n-1) +(3*n-3)*b(n-2))/(n+2))
        end:
    a:= proc(n) a(n):=`if`(n=0, 1, a(n-1)*b(n)) end:
    seq(a(n), n=0..18);  # Alois P. Heinz, Mar 04 2021
  • Mathematica
    Table[Product[Hypergeometric2F1[(1-k)/2, -k/2, 2, 4], {k, 1, n}], {n, 0, 15}]
    FoldList[Times, 1, Table[Hypergeometric2F1[(1 - n)/2, -n/2, 2, 4], {n, 1, 15}]]

Formula

a(n) = Product_{k=1..n} A001006(k).
a(n) ~ c * 3^(n*(n+4)/2) * exp(3*n/2) / (2^(n + 3/4) * Pi^(n/2 + 3/4) * n^(3*n/2 + 51/16)), where c = 1.88710807429950713889649869555827071385924787813206239984338608598135477864...

A342178 Product of first n central Delannoy numbers.

Original entry on oeis.org

1, 3, 39, 2457, 788697, 1327377051, 11931792311439, 580350446236081521, 154215943727867706493809, 225550533306461376412704772467, 1826384842574005591817185497927226551, 82272644789290466599017454496002856892236169
Offset: 0

Views

Author

Vaclav Kotesovec, Mar 04 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n<1, 1,
          (3*(2*n-1)*b(n-1) -(n-1)*b(n-2))/n)
        end:
    a:= proc(n) a(n):=`if`(n=0, 1, a(n-1)*b(n)) end:
    seq(a(n), n=0..15);  # Alois P. Heinz, Mar 04 2021
  • Mathematica
    Table[Product[Hypergeometric2F1[-k, k+1, 1, -1], {k, 1, n}], {n, 0, 15}]
    FoldList[Times, 1, Table[Hypergeometric2F1[-n, n + 1, 1, -1], {n, 1, 15}]]
  • PARI
    D(n) = sum(k=0, n, binomial(n, k)*binomial(n+k, k)); \\ A001850
    a(n) = prod(k=0, n, D(k)); \\ Michel Marcus, Mar 04 2021

Formula

a(n) = Product_{k=1..n} A001850(k).
a(n) ~ c * (1 + sqrt(2))^(n*(n+2)) * exp(n/2) / (2^((5*n+1)/4) * Pi^(n/2 + 1/4) * n^((n+1)/2 - 3/(16*sqrt(2)))), where c = 0.9486848745280397752870611535632702994491680306036912732565033220352175749...
Showing 1-4 of 4 results.