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.

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A133263 Binomial transform of (1, 2, 0, 1, -1, 1, -1, 1, ...).

Original entry on oeis.org

1, 3, 5, 8, 12, 17, 23, 30, 38, 47, 57, 68, 80, 93, 107, 122, 138, 155, 173, 192, 212, 233, 255, 278, 302, 327, 353, 380, 408, 437, 467, 498, 530, 563, 597, 632, 668, 705, 743, 782, 822, 863, 905, 948, 992, 1037, 1083, 1130, 1178, 1227, 1277, 1328, 1380, 1433
Offset: 0

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Author

Gary W. Adamson, Oct 15 2007

Keywords

Comments

A007318 * [1, 2, 0, 1, -1, 1, -1, 1, ...]. Left column of A134249.

Examples

			a(3) = 8 = (1, 3, 3, 1) dot (1, 2 0, 1) = (1 + 6 + 0 + 1).
		

Crossrefs

Programs

  • Maple
    1, seq((n^2+n+4)*1/2,n=1..50); # Emeric Deutsch, Nov 12 2007
    a:=n->add((Stirling2(j+1,n)), j=0..n): seq(a(n)+1, n=0..50); # Zerinvary Lajos, Apr 12 2008
  • Mathematica
    Join[{1},Table[(n^2+n+4)/2,{n,50}]] (* or *) Join[{1}, LinearRecurrence[ {3,-3,1},{3,5,8},50]] (* Harvey P. Dale, Feb 13 2012 *)
  • PARI
    a(n)=n*(n+1)/2+2 \\ Charles R Greathouse IV, Mar 26 2014

Formula

From Emeric Deutsch, Nov 12 2007: (Start)
a(n) = (n^2 + n + 4)/2 for n > 0.
G.f.: (1 - x^2 + x^3)/(1-x)^3. (End)
a(n) = A000124(n) + 1, n >= 1. - Zerinvary Lajos, Apr 12 2008
a(0)=1, a(1)=3; for n >= 2, a(n) = a(n-1) + n. - Philippe Lallouet (philip.lallouet(AT)orange.fr), May 27 2008; corrected by Michel Marcus, Nov 03 2018
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=1, a(1)=3, a(2)=5, a(3)=8. - Harvey P. Dale, Feb 13 2012
a(n) = A238531(n+1) if n >= 0. - Michael Somos, Feb 28 2014
For n > 0: A228446(a(n)) = 5. - Reinhard Zumkeller, Mar 12 2014
a(n) = A022856(n+4) for n >= 1. - Georg Fischer, Nov 02 2018
Sum_{n>=0} 1/a(n) = 1/2 + 2*Pi*tanh(sqrt(15)*Pi/2)/sqrt(25). - Amiram Eldar, Jun 02 2025

Extensions

More terms from Emeric Deutsch, Nov 12 2007

A037235 a(n) = n*(2*n^2 - 3*n + 4)/3.

Original entry on oeis.org

0, 1, 4, 13, 32, 65, 116, 189, 288, 417, 580, 781, 1024, 1313, 1652, 2045, 2496, 3009, 3588, 4237, 4960, 5761, 6644, 7613, 8672, 9825, 11076, 12429, 13888, 15457, 17140, 18941, 20864, 22913, 25092, 27405, 29856, 32449, 35188, 38077, 41120, 44321, 47684, 51213
Offset: 0

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Author

Keywords

Comments

Row sums of triangle A134249. Also, binomial transform of (1, 3, 6, 4, 0, 0, 0, ...). - Gary W. Adamson, Oct 15 2007
Binomial transform of a(n) starts: 0, 1, 6, 28, 112, 400, 1312, 4032, ... . - Wesley Ivan Hurt, Oct 21 2014
Number of equivalence classes of n-tuples from the set {1,0,-1} where at the number of nonzero elements is 1,2, or 3 and two n-tuples are equivalent if they are negatives of each other. - Michael Somos, Oct 19 2022

Crossrefs

Programs

Formula

G.f.: x*(1+3*x^2)/(1-x)^4.
a(n) = Sum_{k=0..n-1} (2*k^2 + 1). - Mike Warburton, Sep 08 2007
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) with n>3, a(0)=0, a(1)=1, a(2)=4, a(3)=13. - Yosu Yurramendi, Sep 03 2013
a(n+1) = a(n) + A058331(n). - Michael Somos, Oct 19 2022
Showing 1-2 of 2 results.