75973

Appears in sequences

• a(n) = 2*n*a(n-1) + 1 with a(0) = 1.at n=6A010844
• Numbers n such that phi(n) = phi(3n+1).at n=0A091294
• Square array, read by antidiagonals: form the Euler-Seidel matrix for the sequence {2^k*k!} and then divide column k by 2^k*k!.at n=21A143411
• Triangle read by rows: T(n,k) = 2*k*T(n-1,n-1) + 1 (n >= 0, 0 <= k <= n), with T(0,0) = 1.at n=27A161380
• Numbers k such that phi(6k) is either phi(6k-2) or phi(6k+2), where phi is Euler's totient function A000010.at n=24A279011
• Numbers k such that phi(6k) = phi(6k+2), where phi is Euler's totient function A000010.at n=9A279184
• Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of the e.g.f. exp(x)/(1 - k*x).at n=42A320031
• Triangle read by rows: T(n, k) = n! * 2^k * hypergeom([-k], [-n], 1/2).at n=27A374428