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.

A061319 Column 4 of A061315.

Original entry on oeis.org

0, 1, 10, 76, 430, 1870, 6601, 19810, 52326, 124785, 273790, 560626, 1083160, 1991626, 3509065, 5957260, 9789076, 15628185, 24317226, 36975520, 55067530, 80483326, 115632385, 163552126, 228032650, 313759225, 426474126, 573159510
Offset: 0

Views

Author

Henry Bottomley, Apr 24 2001

Keywords

Formula

a(n) =A061318(n)/4 =sqrt(A061320(n)-A061318(n)).
G.f. -x*(1+x+22*x^2+22*x^3+22*x^4+x^5+x^6) / (x-1)^9. - R. J. Mathar, Aug 11 2012
a(n) = n*(n+1)*(n^2+n+4)*(n^4+2*n^3+5*n^2+4*n+36)/576 . R. J. Mathar, Aug 11 2012

A061321 Column 5 of A061315.

Original entry on oeis.org

0, 1, 28, 1216, 37324, 700876, 8719921, 78503068, 547643916, 3114359073, 14992411852, 62860750876, 234647983648, 793316418076
Offset: 0

Views

Author

Henry Bottomley, Apr 24 2001

Keywords

Formula

a(n) =A061320(n)/5.

A006007 4-dimensional analog of centered polygonal numbers: a(n) = n(n+1)*(n^2+n+4)/12.

Original entry on oeis.org

0, 1, 5, 16, 40, 85, 161, 280, 456, 705, 1045, 1496, 2080, 2821, 3745, 4880, 6256, 7905, 9861, 12160, 14840, 17941, 21505, 25576, 30200, 35425, 41301, 47880, 55216, 63365, 72385, 82336, 93280, 105281, 118405, 132720, 148296, 165205, 183521
Offset: 0

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Author

Keywords

References

  • S. M. Losanitsch, Die Isomerie-Arten bei den Homologen der Paraffin-Reihe, Chem. Ber. 30 (1897), 1917-1926.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Magma
    [n*(n+1)*(n^2+n+4)/12: n in [0..60]]; // Vincenzo Librandi, Apr 26 2011
    
  • Mathematica
    f[n_]:=n^3;lst={};s=0;Do[s+=(f[n]+f[n+1]+f[n+2]);AppendTo[lst,s/9],{n,0,6!}];lst (* Vladimir Joseph Stephan Orlovsky, Jan 03 2009 *)
    Table[2Binomial[n+2,4]+Binomial[n+1,2],{n,0,40}] (* or *) LinearRecurrence[{5,-10,10,-5,1},{0,1,5,16,40},40] (* Harvey P. Dale, Sep 30 2011 *)
  • PARI
    a(n)=n*(n+1)*(n^2+n+4)/12 \\ Charles R Greathouse IV, Sep 24 2015

Formula

G.f.: (1+x^2)/(1-x)^5.
a(n) = 2*binomial(n + 2, 4) + binomial(n + 1, 2).
a(n) = A061316(n)/3 = A061315(n, 3) = sqrt(A061318(n)-A061316(n)).
a(0)=0, a(1)=1, a(2)=5, a(3)=16, a(4)=40, a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5). - Harvey P. Dale, Sep 30 2011
For n>0, a(n) = (A000217(n-1)^2 + A000217(n)^2 + A000217(n+1)^2 - 1)/9. - Richard R. Forberg, Dec 25 2013
Sum_{n>=1} 1/a(n) = 15/4 - tanh(sqrt(15)*Pi/2)*Pi*sqrt(3/5). - Amiram Eldar, Aug 23 2022
E.g.f.: exp(x)*(12 + 48*x + 42*x^2 + 12*x^3 + x^4)/12. - Stefano Spezia, Aug 31 2023

Extensions

More terms from Henry Bottomley, Apr 24 2001

A061314 Table read by descending antidiagonals where T(n,k) = T(n,k-1) + T(n,k-1)^2/k^2 and T(n,0)=n.

Original entry on oeis.org

0, 0, 1, 0, 2, 2, 0, 3, 6, 3, 0, 4, 15, 12, 4, 0, 5, 40, 48, 20, 5, 0, 6, 140, 304, 120, 30, 6, 0, 7, 924, 6080, 1720, 255, 42, 7, 0, 8, 24640, 1484736, 186620, 7480, 483, 56, 8, 0, 9, 12415040, 61235956672, 1393267596, 3504380, 26404, 840, 72, 9, 0, 10
Offset: 0

Views

Author

Henry Bottomley, Apr 24 2001

Keywords

Comments

Not always an integer.

Examples

			The table begins:
    0,       0,       0,       0,          0,...
    1,       2,       3,       4,          5,...
    2,       6,      15,      40,        140,...
    3,      12,      48,     304,       6080,...
    4,      20,     120,    1720,     186620,...
    5,      30,     255,    7480,    3504380,...
    6,      42,     483,   26404,   43599605,...
    7,      56,     840,   79240,  392515340,...
    8,      72,    1368,  209304, 2738219580,...
    ...
		

Crossrefs

Rows include A000004, A000027 and A061322. Columns include A001477, A002378, A061316, A061318 and A061320.

Formula

T(n, k) = T(n, k-1) + A061315(n, k)^2.
Showing 1-4 of 4 results.