from collections import defaultdict
from bisect import bisect_left,bisect_right
from operator import mul
from functools import reduce

def cmb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(mul, range(n, n - r, -1))
    under = reduce(mul, range(1,r + 1))
    return over // under

N=int(input())
A=list(map(int,input().split()))
keys=set()
D=defaultdict(list)
for i,a in enumerate(A):
    D[a].append(i)
    keys.add(a)
keys=sorted(keys)
cumsum=[0]
for key in keys:
    cumsum.append(cumsum[-1]+len(D[key]))
AA=[]
for k,v in D.items():
    if len(v)>=2:AA.append(k)
ans=0
for a in AA:
    ans+=cmb(len(D[a]),2)*cumsum[bisect_left(keys,a)]
    ans+=cmb(len(D[a]),2)*(cumsum[bisect_left(keys,a*2)]-cumsum[bisect_right(keys,a)])
print(ans)