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 1-6 of 6 results.

A265081 Row 4 of array in A265080.

Original entry on oeis.org

0, 4, 44, 192, 544, 1220, 2364, 4144, 6752, 10404, 15340, 21824, 30144, 40612, 53564, 69360, 88384, 111044, 137772, 169024, 205280, 247044, 294844, 349232, 410784, 480100, 557804, 644544, 740992, 847844, 965820, 1095664, 1238144, 1394052, 1564204, 1749440, 1950624
Offset: 0

Views

Author

N. J. A. Sloane, Jan 01 2016

Keywords

Crossrefs

Cf. A265080.

Extensions

a(6) onwards from Andrew Howroyd, Aug 09 2025

A265082 Row 5 of array in A265080.

Original entry on oeis.org

0, 5, 110, 675, 2540, 7145, 16650, 34055, 63320, 109485, 178790, 278795, 418500, 608465, 860930, 1189935, 1611440, 2143445, 2806110, 3621875, 4615580, 5814585, 7248890, 8951255, 10957320, 13305725, 16038230, 19199835, 22838900, 27007265, 31760370
Offset: 0

Views

Author

N. J. A. Sloane, Jan 01 2016

Keywords

Crossrefs

Cf. A265080.

Extensions

a(6) onwards from Andrew Howroyd, Aug 09 2025

A265083 Column 3 of array in A265080.

Original entry on oeis.org

0, 3, 12, 51, 192, 675, 2358, 8043, 26736, 88659, 290910, 941985, 3046068, 9791613, 31221414, 99466515, 315677664, 996398883, 3143147598, 9888728505, 30988353300, 97066250379, 303448558578, 945804661377, 2946961001304, 9168357598425, 28456994858058, 88302639334743
Offset: 0

Views

Author

N. J. A. Sloane, Jan 01 2016

Keywords

Crossrefs

Cf. A265080.

Programs

  • PARI
    seq(n)={Vec(serlaplace(sum(j=0, n, exp(3*x + O(x*x^n)) - sum(i=0, j, x^i/i!, O(x*x^n))^3)), -n-1)} \\ Andrew Howroyd, Aug 09 2025

Formula

E.g.f.: Sum_{j>=0} (exp(x)^3 - (Sum_{i=0..j} x^i/i!)^3). - Andrew Howroyd, Aug 09 2025

Extensions

a(6) onwards from Andrew Howroyd, Aug 09 2025

A265084 Column 4 of array in A265080.

Original entry on oeis.org

0, 4, 20, 108, 544, 2540, 11544, 52192, 231872, 1014444, 4401400, 19016888, 81588720, 347833408, 1476460496, 6250982640, 26366866432, 110825294252, 464575219704, 1944165731800, 8117172816560, 33813868882584, 140605002878032, 583960731640688, 2421457649730528, 10025040350809600
Offset: 0

Views

Author

N. J. A. Sloane, Jan 01 2016

Keywords

Crossrefs

Cf. A265080.

Programs

  • PARI
    seq(n)={Vec(serlaplace(sum(j=0, n, exp(4*x + O(x*x^n)) - sum(i=0, j, x^i/i!, O(x*x^n))^4)), -n-1)} \\ Andrew Howroyd, Aug 09 2025

Formula

E.g.f.: Sum_{j>=0} (exp(x)^4 - (Sum_{i=0..j} x^i/i!)^4). - Andrew Howroyd, Aug 09 2025

Extensions

a(6) onwards from Andrew Howroyd, Aug 09 2025

A265085 Column 5 of array in A265080.

Original entry on oeis.org

0, 5, 30, 195, 1220, 7145, 40230, 224175, 1241000, 6785325, 36675650, 196823495, 1051855260, 5599171045, 29659801150, 156443274375, 822605274320, 4315160956565, 22584570699690, 117904543416615, 614153114242100, 3193305076085145, 16578603268278590, 85946023037719835
Offset: 0

Views

Author

N. J. A. Sloane, Jan 01 2016

Keywords

Crossrefs

Cf. A265080.

Extensions

a(6) onwards from Andrew Howroyd, Aug 09 2025

A208250 The sum of the largest preimage over all functions f:{1,2,...,n}->{1,2,...,n}.

Original entry on oeis.org

0, 1, 6, 51, 544, 7145, 112356, 2066323, 43574336, 1036922769, 27486891100, 803137535321, 25642631336400, 888148407804853, 33165208812574216, 1328185604750416875, 56783630865774075136, 2581268127178259819297, 124322489582200453748268, 6324172127062894070727625
Offset: 0

Views

Author

Geoffrey Critzer, Jan 15 2013

Keywords

Comments

n labeled balls are placed in n labeled urns. The maximum number of balls in an urn is summed over all n^n possible configurations. a(n) is this sum.

Examples

			a(2) = 6.  The functions f:{1,2}->{1,2} written as words are: 11, 12, 21, 22 and we sum respectively 2 + 1 + 1 + 2 = 6.
		

References

  • R. Sedgewick and P. Flajolet, Analysis of Algorithms, Addison and Wesley, 1996, page 435.

Crossrefs

Main diagonal of A265080.

Programs

  • Mathematica
    f[n_] := n! Coefficient[ Series[ Sum[ Exp[n*x] - Sum[x^i/i!, {i, 0, j}]^n, {j, 0, n}], {x, 0, n}], x^n]; f[0] = 0; Array[f, 19, 0] (* modified by Robert G. Wilson v, Feb 20 2013 *)

Formula

a(n) = n! * [x^n] Sum_{j>=0} (exp(x)^n - (Sum_{i=0..j} x^i/i!)^n).
a(n) ~ n^n log n/log log n. More precisely, a(n)/n^n = Gamma^(-1)(n) - 3/2 + o(1) where Gamma^(-1) is the inverse of the gamma function. See Gönnet section 4 or Mitzenmacher et al. - Charles R Greathouse IV, Feb 20 2013
Showing 1-6 of 6 results.