664335
domain: N
Appears in sequences
- a(n) = 9*binomial(n,4) = 3*n*(n-1)*(n-2)*(n-3)/8.at n=38A060008
- Odd numbers k such that k and phi(k) have the same number of divisors.at n=9A116518
- Triangle defined by T(n,k) = T(n-1,k-1) + Sum_{j=k..n-2} T(n-1,j)*2^j*T(j,k-1) for n>k>0 with T(n,n)=T(n,0)=1, read by rows.at n=38A152795
- Column 2 of triangle A152795.at n=6A152797