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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A335390 a(n) = Sum_{k=0..n} Stirling2(n,k) * 2^binomial(k,2). 1
 1, 1, 3, 15, 127, 1895, 53071, 2953575, 337064047, 79446381319, 38491200186831, 38046637826801703, 76226441027901385519, 308075833912652114006087, 2503633988838391023366024079, 40826169678526460459483237927271, 1334110729147927667553970495057395439 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Stirling transform of A006125. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..82 FORMULA G.f.: Sum_{k>=0} 2^binomial(k,2) * x^k / Product_{j=1..k} (1 - j*x). E.g.f.: Sum_{k>=0} 2^binomial(k,2) * (exp(x) - 1)^k / k!. a(n) ~ 2^(n*(n-1)/2). - Vaclav Kotesovec, Jun 05 2020 MAPLE a:= n-> add(Stirling2(n, k)*2^(k*(k-1)/2), k=0..n): seq(a(n), n=0..19); # Alois P. Heinz, Jun 05 2020 MATHEMATICA Table[Sum[StirlingS2[n, k] 2^Binomial[k, 2], {k, 0, n}], {n, 0, 16}] PROG (PARI) a(n) = sum(k=0, n, stirling(n, k, 2) * 2^binomial(k, 2)); \\ Michel Marcus, Jun 05 2020 CROSSREFS Cf. A006024, A006125. Sequence in context: A135255 A182489 A330804 * A075475 A074241 A228365 Adjacent sequences: A335387 A335388 A335389 * A335391 A335392 A335393 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Jun 04 2020 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 March 25 07:51 EDT 2023. Contains 361511 sequences. (Running on oeis4.)