19877

Appears in sequences

• a(n) = (6*n+1)*(6*n+5).at n=23A001513
• a(n) = A026615(2*n, n-1).at n=7A026617
• One half of sixth column (m=5) of triangle A060556.at n=5A060559
• Integers n > 1997 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 1997.at n=37A063055
• Numbers n such that phi(n-1) + phi(n+1) = phi(2n).at n=12A067701
• Number of unlabeled and connected graphs on n vertices which have no induced subgraph isomorphic to the 'fork' (fork = 4 vertices forming a path with a fifth vertex adjacent only to one of the non-end vertices).at n=8A079468
• a(n) = (4*n+3)*(4*n+7).at n=34A085027
• Second trisection of A061037.at n=46A142599
• a(n) = (8*n+3)*(8*n+7).at n=17A146301
• Smallest k such that 38^k mod k = n.at n=25A178199
• a(n) = Sum_{d|n} C(n,d)*sigma(d).at n=14A179305
• Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having one, three, four, five or six distinct values for every i,j,k<=n.at n=7A211579
• Number of closed normal forms of size n in lambda calculus with size 0 for the variables.at n=6A224345
• Composite squarefree numbers n such that p(i)+5 divides n-5, where p(i) are the prime factors of n.at n=8A225715
• Triangle read by rows: T(n,k) = Sum_{j=k..n} binomial(n + j, n)*binomial(n, j)/(j + 1).at n=42A351385
• Irregular triangle read by rows: T(n,k) is the number of free polyaboloes (or polytans) with n cells of which 2*k share a hypotenuse in pairs (making up k squares), 0 <= k <= n/2.at n=39A391191
• Triangle read by rows: T(n,k) is the number of free polyaboloes (or polytans) with n cells (counted as in A390996) of which k are square cells consisting of two triangles sharing a hypotenuse, 0 <= k <= n.at n=39A391192