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 1-5 of 5 results.

A113869 Coefficients in asymptotic expansion of probability that a random pair of elements from the alternating group A_k generates all of A_k.

Original entry on oeis.org

1, -1, -1, -4, -23, -171, -1542, -16241, -194973, -2622610, -39027573, -636225591, -11272598680, -215668335091, -4431191311809, -97316894892644, -2275184746472827, -56421527472282127, -1479397224086870294, -40897073524132164189, -1188896226524012279617
Offset: 0

Views

Author

N. J. A. Sloane, Jan 26 2006

Keywords

Crossrefs

Programs

Formula

The probability that a random pair of elements from the alternating group A_k generates all of A_k is P_k ~ 1-1/k-1/k^2-4/k^3-23/k^4-171/k^5-... = Sum_{n >= 0} a(n)/k^n.
Furthermore, P_k ~ 1 - Sum_{n >= 1} A003319(n)/[k]n, where [k]_n = k(k-1)(k-2)...(k-n+1). Therefore for n >= 2, a(n) = - Sum{i=1..n} A003319(i)*Stirling_2(n-1, i-1). - N. J. A. Sloane.
a(n) ~ -n! / (4 * (log(2))^(n+1)). - Vaclav Kotesovec, Jul 28 2015

A114038 Analog of A113869 for three generators.

Original entry on oeis.org

1, 0, -1, 0, -3, -6, -38, -186, -1181, -8094, -61865, -516702, -4688020, -45887352, -481954769, -5406249972, -64506680939, -815807306442, -10901200843386, -153475188129114, -2270769144678657, -35226976789341426, -571781884343282417, -9691701188493783546
Offset: 0

Views

Author

N. J. A. Sloane, Feb 01 2006

Keywords

Crossrefs

Related to A113871 in the same way that A113869 is related to A003319.

Programs

  • Mathematica
    nmax=30; A113871 = Rest[CoefficientList[Series[1/Sum[(k!)^2 x^k,{k,0,nmax}],{x,0,nmax}],x]]; Table[SeriesCoefficient[1 + Sum[A113871[[j]]/Product[n-i+1,{i,1,j}]^2,{j,1,nmax}],{n,Infinity,k}],{k,0,nmax}] (* Vaclav Kotesovec, Jul 28 2015 *)

Formula

a(n) ~ -Pi * n^(n+1) / (2^(n+4) * exp(n) * (log(2))^(n+3/2)). - Vaclav Kotesovec, Jul 28 2015

Extensions

Missing a(3)=0 and more terms added by Vaclav Kotesovec, Jul 28 2015

A316862 Expansion of 1/(Sum_{k>=0} (k!)^3 x^k).

Original entry on oeis.org

1, -1, -7, -201, -13351, -1697705, -369575303, -127249900617, -65286578868455, -47651775381867241, -47688241963081263175, -63505249400026210723209, -109775495351620406817045415, -241236985075124408660287423529, -662075390371447206867029299628807
Offset: 0

Views

Author

Seiichi Manyama, Jul 15 2018

Keywords

Crossrefs

1/(Sum_{k>=0} (k!)^b x^k): A167894 (b=1), A113871 (b=2), this sequence (b=3).
Cf. A000442.

Programs

  • Mathematica
    a[n_] := -Sum[(k!)^3*a[n - k], {k, n}]; a[0] = 1; Array[a, 15, 0] (* Robert G. Wilson v, Jul 15 2018 *)
    nmax = 20; CoefficientList[Series[1/Sum[k!^3 * x^k, {k, 0, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Dec 08 2020 *)

Formula

a(0) = 1, a(n) = -Sum_{k=1..n} (k!)^3 * a(n-k).
a(n) ~ -(n!)^3 * (1 - 2/n^3 - 13/n^6 - 39/n^7 - 78/n^8 - 518/n^9 - 3687/n^10 - ...). - Vaclav Kotesovec, Dec 08 2020

A306629 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of 1/(Sum_{j>=0} (j!)^k * x^j).

Original entry on oeis.org

1, 1, -1, 1, -1, 0, 1, -1, -1, 0, 1, -1, -3, -3, 0, 1, -1, -7, -29, -13, 0, 1, -1, -15, -201, -499, -71, 0, 1, -1, -31, -1265, -13351, -13101, -461, 0, 1, -1, -63, -7713, -328975, -1697705, -486131, -3447, 0, 1, -1, -127, -46529, -7946143, -206659569, -369575303, -24266797, -29093, 0
Offset: 0

Views

Author

Seiichi Manyama, Mar 02 2019

Keywords

Examples

			Square array begins:
    1,    1,       1,          1,             1, ...
   -1,   -1,      -1,         -1,            -1, ...
    0,   -1,      -3,         -7,           -15, ...
    0,   -3,     -29,       -201,         -1265, ...
    0,  -13,    -499,     -13351,       -328975, ...
    0,  -71,  -13101,   -1697705,    -206659569, ...
    0, -461, -486131, -369575303, -268312660751, ...
		

Crossrefs

Columns 1-3 give A167894, A113871, A316862.
Rows 0-2 give A000012, (-1)*A000012, (-1)*A000225.
Main diagonal gives A306630.

Formula

A(0,k) = 1 and A(n,k) = -Sum_{j=1..n} (j!)^k * A(n-j,k) for n > 0.

A114039 Expansion of g.f. 1/Sum_{k>=0} k!*(k!+1)*x^k/2.

Original entry on oeis.org

1, -1, -2, -16, -257, -6613, -243980, -12155224, -786429623, -64166829085, -6449457120962, -783277824629140, -113105715390915929, -19155829563735891169, -3760880464339217383124, -847344181950467763488740, -217159542960607254804746279, -62816327344923649504400271697
Offset: 0

Views

Author

N. J. A. Sloane, Feb 01 2006

Keywords

Crossrefs

Cf. A113871.

Programs

  • Mathematica
    nmax=17; CoefficientList[Series[1/Sum[k!*(k!+1)*x^k/2,{k,0,nmax}],{x,0,nmax}],x] (* Stefano Spezia, Oct 09 2023 *)
Showing 1-5 of 5 results.