login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Derangement numbers d(n,4) where d(n,k) = k(n-1)(d(n-1,k) + d(n-2,k)), with d(0,k) = 1 and d(1,k) = 0.
7

%I #12 Oct 10 2013 05:19:05

%S 1,0,4,32,432,7424,157120,3949056,114972928,3805503488,141137150976,

%T 5797706178560,261309106499584,12821127008550912,680286677982625792,

%U 38814037079505895424,2369659425449311272960,154142301601844298776576,10642813349855965483368448

%N Derangement numbers d(n,4) where d(n,k) = k(n-1)(d(n-1,k) + d(n-2,k)), with d(0,k) = 1 and d(1,k) = 0.

%H Vincenzo Librandi, <a href="/A088991/b088991.txt">Table of n, a(n) for n = 0..200</a>

%F Inverse binomial transform of A007696. E.g.f.: exp(-x)/(1-4*x)^(1/4). - _Vladeta Jovovic_, Dec 17 2003

%F a(n) ~ n^(n-1/4) * Gamma(3/4) * 4^n / (sqrt(Pi)*exp(n+1/4)). - _Vaclav Kotesovec_, Oct 08 2013

%t CoefficientList[Series[E^(-x)/(1-4*x)^(1/4), {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Oct 08 2013 *)

%Y Cf. A000166, A053871, A033030, A088992.

%K nonn,easy

%O 0,3

%A _N. J. A. Sloane_, Nov 02 2003