The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A353254 Expansion of Sum_{k>=0} x^k * Product_{j=0..k-1} (j - 2 * x). 4
 1, 0, -2, -2, 0, 0, -12, -88, -608, -4664, -40032, -381200, -3993520, -45685472, -566975456, -7589393568, -109019255360, -1673050977024, -27321358963904, -473094230383616, -8659054324278528, -167044915214322816, -3387793305708038400, -72061754672510128384 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..23. FORMULA a(n) = Sum_{k=0..floor(n/2)} (-2)^k * |Stirling1(n-k,k)|. MATHEMATICA a[n_] := Sum[(-2)^k * Abs[StirlingS1[n - k, k]], {k, 0, Floor[n/2]}]; Array[a, 25, 0] (* Amiram Eldar, Apr 09 2022 *) PROG (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, x^k*prod(j=0, k-1, j-2*x))) (PARI) a(n) = sum(k=0, n\2, (-2)^k*abs(stirling(n-k, k, 1))); CROSSREFS Cf. A343579, A353252, A353253. Cf. A353261. Sequence in context: A122670 A352661 A283494 * A281034 A282441 A281988 Adjacent sequences: A353251 A353252 A353253 * A353255 A353256 A353257 KEYWORD sign AUTHOR Seiichi Manyama, Apr 08 2022 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 12 04:24 EDT 2024. Contains 375085 sequences. (Running on oeis4.)