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.

Previous Showing 21-29 of 29 results.

A029868 Number of connected functions on n points with a loop of length 5.

Original entry on oeis.org

1, 1, 4, 14, 46, 145, 440, 1315, 3877, 11315, 32792, 94529, 271510, 777764, 2223865, 6350657, 18120730, 51680249, 147359335, 420163711, 1198151432, 3417475326, 9750708533, 27831153091, 79471338455, 227032777454, 648896436944, 1855571389651, 5308837191604
Offset: 5

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Crossrefs

Column 5 of A339428.

Programs

  • Mathematica
    nn = 20; f[x_] := Sum[a[n] x^n, {n, 0, nn}]; sol =
    SolveAlways[
      0 == Series[
        f[x] - x Product[1/(1 - x^i)^a[i], {i, 1, nn}], {x, 0, nn}],
      x]; b = Flatten[Table[a[n], {n, 1, nn}] /. sol]; CoefficientList[
    Series[CycleIndex[CyclicGroup[5], s] /.
       Table[s[i] -> Sum[b[[k]] x^(k*i), {k, 1, nn}], {i, 1, 5}], {x, 0,
    nn}], x] (* Geoffrey Critzer, Aug 08 2013 *)

Formula

"CIK[ 5 ]" (necklace, indistinct, unlabeled, 5 parts) transform of A000081.
G.f.: A(x) = ( B(x)^5 +4*B(x^5) )/5 where B(x) is the o.g.f. for A000081. - Geoffrey Critzer, Aug 09 2013
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

A029869 Number of connected functions on n points with a loop of length 6.

Original entry on oeis.org

1, 1, 5, 18, 63, 206, 671, 2087, 6434, 19472, 58375, 173316, 511452, 1500697, 4386021, 12775455, 37118209, 107621858, 311552351, 900775893, 2601887149, 7510011727, 21664873773, 62473966631, 180104101037, 519126161517, 1496177366884, 4312044894059, 12427896986697
Offset: 6

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Column 6 of A339428.

Formula

"CIK[ 6 ]" (necklace, indistinct, unlabeled, 6 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(31) and beyond from Andrew Howroyd, Dec 08 2020

A029870 Number of connected functions on n points with a loop of length 7.

Original entry on oeis.org

1, 1, 5, 21, 80, 285, 970, 3192, 10236, 32197, 99743, 305276, 925342, 2783012, 8316994, 24726109, 73195582, 215911767, 635028054, 1863156727, 5455350409, 15946267328, 46545783253, 135702643984, 395246786050, 1150250414764, 3345193851398, 9723141517918
Offset: 7

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Column 7 of A339428.

Formula

"CIK[ 7 ]" (necklace, indistinct, unlabeled, 7 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(32) and beyond from Andrew Howroyd, Dec 04 2020

A029871 Number of connected functions on n points with a loop of length 8.

Original entry on oeis.org

1, 1, 6, 25, 104, 384, 1380, 4729, 15806, 51478, 164788, 519296, 1617066, 4983855, 15233671, 46235252, 139506803, 418838281, 1252174861, 3730058316, 11077154790, 32808815240, 96953599162, 285945645659, 841909040785, 2475184643011, 7267678432397, 21315839832323
Offset: 8

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Column 8 of A339428.

Formula

"CIK[ 8 ]" (necklace, indistinct, unlabeled, 8 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(32) and beyond from Andrew Howroyd, Dec 04 2020

A032205 Number of connected functions on n points with a loop of length 9.

Original entry on oeis.org

1, 1, 6, 30, 127, 506, 1902, 6823, 23673, 79936, 264036, 856772, 2739525, 8652707, 27049259, 83824636, 257847515, 788121922, 2395786374, 7248517868, 21840785100, 65574504200, 196266067194, 585822825763, 1744384025528, 5183186173513, 15372268502463, 45515472900289
Offset: 9

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Column 9 of A339428.

Formula

"CIK[ 9 ]" (necklace, indistinct, unlabeled, 9 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(33) and beyond from Andrew Howroyd, Dec 04 2020

A032206 Number of connected functions on n points with a loop of length 10.

Original entry on oeis.org

1, 1, 7, 34, 158, 655, 2578, 9619, 34659, 120966, 412214, 1375861, 4516058, 14611989, 46712942, 147798787, 463512254, 1442513910, 4459548539, 13706894100, 41915906463, 127607366453, 386953440455, 1169295277193, 3522431890950, 10581852932516, 31711045921908
Offset: 10

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Column 10 of A339428.

Formula

"CIK[ 10 ]" (necklace, indistinct, unlabeled, 10 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(34) and beyond from Andrew Howroyd, Dec 04 2020

A032207 Number of connected functions on n points with a loop of length 11.

Original entry on oeis.org

1, 1, 7, 39, 189, 832, 3415, 13289, 49594, 178972, 628397, 2156842, 7263306, 24068685, 78667879, 254101597, 812408511, 2574398860, 8094625175, 25278311063, 78465711029, 242265995076, 744465052503, 2278029840583, 6944364119469, 21097626446747, 63901611553272
Offset: 11

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Column 11 of A339428.

Formula

"CIK[ 11 ]" (necklace, indistinct, unlabeled, 11 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(35) and beyond from Andrew Howroyd, Dec 04 2020

A032208 Number of connected functions on n points with a loop of length 12.

Original entry on oeis.org

1, 1, 8, 45, 229, 1043, 4474, 18034, 69698, 259516, 938342, 3308793, 11427018, 38763095, 129499981, 426937452, 1391429896, 4489322347, 14356694844, 45554354359, 143546523999, 449545164857, 1400098598183, 4339078154900, 13387747332571, 41141433154653
Offset: 12

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Column 12 of A339428.

Formula

"CIK[ 12 ]" (necklace, indistinct, unlabeled, 12 parts) transform of A000081.
a(n) ~ A187770 * A051491^n / n^(3/2). - Vaclav Kotesovec, Dec 25 2020

Extensions

Terms a(35) and beyond from Andrew Howroyd, Dec 04 2020

A261875 Decimal expansion of the coefficient 'gamma' (see formula) appearing in Otter's result concerning the asymptotics of T_n, the number of non-isomorphic rooted trees of order n.

Original entry on oeis.org

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

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Author

Jean-François Alcover, Sep 04 2015

Keywords

Examples

			2.68112814726711223857732878370393709354175347201161663527497...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.6 Otter's tree enumeration constants, p. 296.

Crossrefs

Programs

  • Mathematica
    digits = 100; max = 250; Clear[s, a]; s[n_, k_] := s[n, k] = a[n + 1 - k] + If[n < 2*k, 0, s[n-k, k]]; a[1] = 1; a[n_] := a[n] = Sum[a[k]*s[n-1, k]*k, {k, 1, n-1}]/(n-1); A[x_] := Sum[a[k]*x^k, {k, 0, max}]; APrime[x_] := Sum[k*a[k]*x^(k-1), {k, 0, max}]; eq = Log[c] == 1 + Sum[A[c^-k]/k, {k, 2, max}]; alpha = c /. FindRoot[eq, {c, 3}, WorkingPrecision -> digits+5]; beta = (1+Sum[APrime[alpha^(-k)]/alpha^k, {k, 2, max}])^(3/2)/Sqrt[2*Pi]; gamma = 2^(2/3)*Pi^(1/6)*beta^(1/3) * Sqrt[alpha]; RealDigits[gamma, 10, digits] // First

Formula

Lim_{n->infinity} T_n*n^(3/2)/alpha^n = (beta/(2 Pi))^(1/3) = (1/(4 Pi alpha))^(1/2)*gamma, where alpha is A051491 and beta is A086308.
gamma = 2^(2/3)*Pi^(1/6)*beta^(1/3)*sqrt(alpha).
Previous Showing 21-29 of 29 results.