OFFSET
1,2
FORMULA
a(1)=1, a(2)=2, a(n+1) = ((n^2 + n - 1)*a(n) - n*a(n-1))/(n-1) (n >= 2). - Emeric Deutsch, Apr 18 2005
a(n) ~ c * n * n!, where c = BesselJ(2,2) = 0.3528340286156377191506207876191884610951482075010678369927893147532331585216... - Vaclav Kotesovec, Jul 13 2021, updated Sep 24 2023
MAPLE
a[1]:=1:a[2]:=2: for n from 2 to 30 do a[n+1]:=((n^2+n-1)*a[n]-n*a[n-1])/(n-1) od:seq(a[n], n=1..23); # Emeric Deutsch, Apr 18 2005
MATHEMATICA
RecurrenceTable[{a[1]==1, a[2]==2, a[n+1] == ((n^2 + n - 1)*a[n] - n*a[n-1])/(n-1)}, a, {n, 1, 20}] (* Vaclav Kotesovec, Jul 13 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Apr 26 2004
EXTENSIONS
More terms from Emeric Deutsch, Apr 18 2005
STATUS
approved