1562400

Appears in sequences

• Irrational unitary phi amicable number: numbers b such that uphi(a) = uphi(b) = 2*(a^2-b^2)^(1/2) where uphi = A047994.at n=2A046709
• a(1)=1. a(n) is the smallest positive multiple of n that has more divisors than a(n-1) has.at n=30A143176
• Triangular array read by rows. T(n,k) is the number of n X n matrices over GF(2) with index k, n>=1, 1<=k<=n.at n=13A358433