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.

A132754 a(n) = n*(n + 23)/2.

Original entry on oeis.org

0, 12, 25, 39, 54, 70, 87, 105, 124, 144, 165, 187, 210, 234, 259, 285, 312, 340, 369, 399, 430, 462, 495, 529, 564, 600, 637, 675, 714, 754, 795, 837, 880, 924, 969, 1015, 1062, 1110, 1159, 1209, 1260, 1312, 1365, 1419, 1474, 1530
Offset: 0

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Author

Omar E. Pol, Aug 28 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[n (n + 23)/2, {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 12, 25}, 50] (* Harvey P. Dale, Jun 21 2011 *)
  • PARI
    a(n)=n*(n+23)/2 \\ Charles R Greathouse IV, Jun 16 2017

Formula

a(n) = n*(n + 23)/2.
Let f(n,i,a) = Sum_{k=0..n-i} (binomial(n,k)*Stirling1(n-k,i)*Product_{j=0..k-1} (-a-j)), then a(n) = -f(n,n-1,12), for n>=1. - Milan Janjic, Dec 20 2008
a(n) = n + a(n-1) + 11, with a(0)=0. - Vincenzo Librandi, Aug 03 2010
a(0)=0, a(1)=12, a(2)=25, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, Jun 21 2011
a(n) = 12*n - floor(n/2) + floor(n^2/2). - Wesley Ivan Hurt, Jun 15 2013
From Amiram Eldar, Jan 10 2021: (Start)
Sum_{n>=1} 1/a(n) = 2*A001008(23)/(23*A002805(23)) = 444316699/1368302936.
Sum_{n>=1} (-1)^(n+1)/a(n) = 4*log(2)/23 - 3825136961/61573632120. (End)
From Elmo R. Oliveira, Nov 29 2024: (Start)
G.f.: x*(11*x - 12)/(x-1)^3.
E.g.f.: exp(x)*x*(24 + x)/2.
a(n) = A132765(n)/2. (End)