47736
domain: N
Appears in sequences
- Integers y such that for some integer x we have uphi(x) = uphi(y) = x-y, where uphi(n) = A047994(n) is the unitary totient function: If n = Product p_i^e_i, uphi(n) = Product (p_i^e_i - 1).at n=14A067741
- Number of 1:3:sqrt(10) proportioned triangles on a (n+1) X (n+1) grid.at n=21A190102
- Numbers with prime factorization p*q*r^3*s^3 (where p, q, r, s are distinct primes).at n=26A190108
- Antidiagonal sums of the convolution array A213778.at n=30A213780
- E.g.f.: Sum_{n>=0} (n*y + x^n)^n / n! - Sum_{n>=0} n^n*y^n / n! at y=1.at n=5A265270
- a(n) = 4*n*(n^2 - 3*n - 1)/3.at n=34A275876
- a(n) = (n + 1)^2*a(n - 2) + a(n - 1), starting 0, 9, ....at n=6A335026