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.

A053581 First differences of the Poly-Bernoulli numbers B_n^(k) with k=-2 (A027649).

Original entry on oeis.org

1, 3, 10, 32, 100, 308, 940, 2852, 8620, 25988, 78220, 235172, 706540, 2121668, 6369100, 19115492, 57362860, 172121348, 516429580, 1549419812, 4648521580, 13946089028, 41839315660, 125520044132
Offset: 0

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Author

Barry E. Williams, Jan 18 2000

Keywords

Comments

Also the second differences of A001047.
Equals sum of "terms added" to current row of the triangle version of A038573 to get the next row. a(3) = 32 sum of (3, 7, 7, 15) = terms appended to row 2 of the triangle in A038573. - Gary W. Adamson, Jun 04 2009

Crossrefs

Cf. A001045.
Cf. A038573. - Gary W. Adamson, Jun 04 2009

Programs

  • GAP
    List([0..30], n-> 4*3^(n-1) +(0^n -3*2^n)/6) # G. C. Greubel, May 16 2019
  • Magma
    [4*3^n/3+0^n/6-2^n/2: n in [0..30]]; // Vincenzo Librandi, Jul 17 2011
    
  • Mathematica
    CoefficientList[Series[(1-x)^2/((1-2x)(1-3x)),{x,0,30}],x]  (* Harvey P. Dale, Apr 22 2011 *)
  • PARI
    vector(30, n, n--; 4*3^(n-1) +(0^n -3*2^n)/6) \\ G. C. Greubel, May 16 2019
    
  • Sage
    [4*3^(n-1) +(0^n -3*2^n)/6 for n in (0..30)] # G. C. Greubel, May 16 2019
    

Formula

a(n) = 5*a(n-1) - 6*a(n-2) + C(2,2-n), n>1, with a(0)=1, a(1)=3, where C(2, 2-n)=1 for n=2 and =0 for n>2.
From Paul Barry, Jun 26 2003: (Start)
Binomial transform of A000975(n+1).
G.f.: (1-x)^2/((1-2*x)*(1-3*x)).
a(n) = 4*3^n/3 + 0^n/6 - 2^n/2. (End)
a(n) = Sum_{k=0..n+1} binomial(n+1, k) * Sum_{j=0..floor(k/2)} A001045(k-2*j). - Paul Barry, Apr 17 2005
E.g.f.: (1 - 3*exp(2*x) + 8*exp(3*x))/6. - G. C. Greubel, May 16 2019