19384

Appears in sequences

• Row sums of triangle A049410.at n=7A049426
• Interprimes which are of the form s*prime, s=8.at n=28A075283
• 3*Sum_{k>=0} k^n/binomial(2*k, k) = Pi*sqrt(3)*q(n) + a(n) for some rational sequence (q(n)).at n=9A098830
• Nondescending wiggly sums: number of sums adding to n in which terms alternately do not decrease and do not increase.at n=19A129852
• G.f. A(x) satisfies: A(x) = Sum_{n>=0} [x*A(x)]^(2^n-1).at n=13A134527
• Numbers n such that gcd(n, phi(n)) = gcd(phi(n), sigma(n)) = gcd(sigma(n), n) = tau(n).at n=34A217301
• Triangle read by rows: T(n,k) is the coefficient A_k in the transformation Sum_{k=0..n} (k+1)*x^k = Sum_{k=0..n} A_k*(x+3)^k.at n=31A246798
• Number of length 3 1..(n+2) arrays with no leading or trailing partial sum equal to a prime and no consecutive values equal.at n=42A254220
• Numbers n such that the Collatz iterations for n and n + 1 have the same length (A078417) but do not meet a certain condition. (See comments.)at n=27A274410
• Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(Sum_{j=1..k+1} binomial(k,j-1)*x^j/j).at n=62A293991
• G.f. satisfies A(x) = 1 + x*A(x)*(1 + x^5*A(x)^4).at n=17A365798