8589737985

Appears in sequences

• a(n) = binomial(2^n-1,2).at n=17A134057
• M(M-1)/2, where M is Mersenne prime A000668(n).at n=5A139224
• a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 17.at n=1A161215