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 1-3 of 3 results.

A354286 Expansion of e.g.f. 1/(1 - x)^(2/(1 + 2 * log(1-x))).

Original entry on oeis.org

1, 2, 14, 144, 1936, 32000, 625952, 14117152, 360175584, 10246079616, 321313928448, 11006050602624, 408662128569984, 16344011453662464, 700254206319007488, 31990601456727585792, 1551985176120589820928, 79669906174753878177792
Offset: 0

Views

Author

Seiichi Manyama, May 23 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-x)^(2/(1+2*log(1-x)))))
    
  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, sum(k=0, j, 2^k*k!*abs(stirling(j, k, 1)))*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A088500(k) * binomial(n-1,k-1) * a(n-k).
a(n) = Sum_{k=0..n} 2^k * A000262(k) * |Stirling1(n,k)|.
a(n) ~ n^(n - 1/4) / (2^(3/4) * (exp(1/2) - 1)^(n + 1/4) * exp(3/4 - 1/(4*(exp(1/2) - 1)) - sqrt(2*n/(exp(1/2) - 1)) + n/2)). - Vaclav Kotesovec, May 23 2022

A354287 Expansion of e.g.f. 1/(1 - x)^(3/(1 + 3 * log(1-x))).

Original entry on oeis.org

1, 3, 30, 438, 8334, 194580, 5368662, 170591022, 6126386724, 245127214548, 10804866210648, 519910458588576, 27105081897342816, 1521393008601586536, 91445577404393807928, 5858664681621903625368, 398467273528657973600208, 28668189882264862351707504
Offset: 0

Views

Author

Seiichi Manyama, May 23 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-x)^(3/(1+3*log(1-x)))))
    
  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, sum(k=0, j, 3^k*k!*abs(stirling(j, k, 1)))*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A354263(k) * binomial(n-1,k-1) * a(n-k).
a(n) = Sum_{k=0..n} 3^k * A000262(k) * |Stirling1(n,k)|.
a(n) ~ exp((-5 + 1/(exp(1/3) - 1) + 4*sqrt(3*n/(exp(1/3) - 1)) - 4*n)/6) * n^(n - 1/4) / (sqrt(2) * 3^(1/4) * (exp(1/3) - 1)^(n + 1/4)). - Vaclav Kotesovec, May 23 2022

A256548 Triangle read by rows, T(n,k) = |n,k|*h(k), where |n,k| are the Stirling cycle numbers and h(k) = hypergeom([-k+1,-k],[],1), for n>=0 and 0<=k<=n.

Original entry on oeis.org

1, 0, 1, 0, 1, 3, 0, 2, 9, 13, 0, 6, 33, 78, 73, 0, 24, 150, 455, 730, 501, 0, 120, 822, 2925, 6205, 7515, 4051, 0, 720, 5292, 21112, 53655, 87675, 85071, 37633, 0, 5040, 39204, 170716, 494137, 981960, 1304422, 1053724, 394353
Offset: 0

Views

Author

Peter Luschny, Apr 12 2015

Keywords

Examples

			Triangle starts:
[1]
[0,   1]
[0,   1,   3]
[0,   2,   9,   13]
[0,   6,  33,   78,   73]
[0,  24, 150,  455,  730,  501]
[0, 120, 822, 2925, 6205, 7515, 4051]
		

Crossrefs

Programs

  • Sage
    A000262 = lambda n: simplify(hypergeometric([-n+1, -n], [], 1))
    A256548 = lambda n,k: A000262(k)*stirling_number1(n,k)
    for n in range(7): [A256548(n,k) for k in (0..n)]

Formula

T(n,k) = A132393(n,k)*A000262(k).
T(n,n) = A000262(n).
T(n+1,1) = n!.
Row sums are A088815.
Alternating row sums are (-1)^n*A088819(n).
Showing 1-3 of 3 results.