OFFSET
0,1
LINKS
FORMULA
a(n) = 2*a(n-1) - a(n-2) + a(n-3) - a(n-4) (holds at least up to n = 50000 but is not known to hold in general).
MAPLE
L := proc(a0, a1, n)
option remember;
if n = 0 then
a0 ;
elif n = 1 then
a1;
else
ceil( procname(a0, a1, n-1)^2/procname(a0, a1, n-2)) ;
end if;
end proc:
A048585 := proc(n)
L(6, 7, n) ;
end proc:
MATHEMATICA
RecurrenceTable[{a[0] == 6, a[1] == 7, a[n] == Ceiling[a[n - 1]^2/a[n - 2]]}, a, {n, 0, 50}] (* Bruno Berselli, Feb 05 2016 *)
PROG
(Magma) Lxy:=[6, 7]; [n le 2 select Lxy[n] else Ceiling(Self(n-1)^2/Self(n-2)): n in [1..50]]; // Bruno Berselli, Feb 05 2016
(PARI) first(n)=my(v=vector(n+1)); v[1]=6; v[2]=7; for(i=3, #v, v[i]=ceil(v[i-1]^2/v[i-2])); v \\ Charles R Greathouse IV, Feb 12 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved