cp's OEIS Frontend

A133471 a(n) = (n^2)*a(n-1) + a(n-2).

%I A133471 #24 Oct 08 2018 04:14:29
%S A133471 0,1,4,37,596,14937,538328,26393009,1689690904,136891356233,
%T A133471 13690825314204,1656726754374917,238582343455302252,
%U A133471 40322072770700455505,7903364845400744581232,1778297412287938231232705,455252040910557587940153712,131569618120563430852935655473
%N A133471 a(n) = (n^2)*a(n-1) + a(n-2).
%C A133471 Alternates between even and odd.
%C A133471 After a(3) = 37, which is the next prime?
%C A133471 Next primes are a(9) = 136891356233, a(51) = 2.5... * 10^132, a(249) = 1.7... * 10^980. - _Charles R Greathouse IV_, Mar 13 2015
%C A133471 Same as A036245 except for n=0. - _Georg Fischer_, Oct 07 2018
%H A133471 Georg Fischer, <a href="/A133471/b133471.txt">Table of n, a(n) for n = 0..255</a>
%p A133471 A133471 := proc(n)
%p A133471     if n <= 1 then
%p A133471         n;
%p A133471     else
%p A133471         n^2*procname(n-1)+procname(n-2) ;
%p A133471     end if;
%p A133471 end proc: # _R. J. Mathar_, Sep 23 2016
%t A133471 RecurrenceTable[{a[0]==0,a[1]==1,a[n]==n^2 a[n-1]+a[n-2]},a,{n,30}] (* or *) Module[{nn=20,frac},frac=Range[nn]^2;Join[{0},Table[Denominator[ FromContinuedFraction[Take[frac,n]]],{n,nn}]]] (* _Harvey P. Dale_, Mar 14 2015 *)
%o A133471 (PARI) v=vector(100); v[1]=1;v[2]=4; for(n=3,#v, v[n]=n^2*v[n-1]+v[n-2]); v=concat(0,v) \\ _Charles R Greathouse IV_, Mar 13 2015
%o A133471 (GAP) a:=[0,1];; for n in [3..20] do a[n]:=(n-1)^2*a[n-1]+a[n-2]; od; a; # _Muniru A Asiru_, Oct 07 2018
%Y A133471 Cf. A000045, A000290, A001040.
%K A133471 easy,nonn
%O A133471 0,3
%A A133471 _Jonathan Vos Post_, Nov 28 2007
%E A133471 Terms and definition corrected by _Harvey P. Dale_, Mar 13 2015