19025

Appears in sequences

• Least k such that Sum_{i=1..k} (prime(i) + prime(i+2) - 2*prime(i+1)) = 2n + 1.at n=37A073051
• G.f.: A(x) = Sum_{n>=0} x^n * Product_{k=1..n} (2^(2*k-1) - 1) / (1 + 2^(2*k-1)*x).at n=4A214691
• a(n) = smallest m such that A031131(m) = 2*n.at n=45A261525
• a(n) = smallest k with concat(1,k) and concat(n,k) both square numbers.at n=8A265432
• Numbers m such that the decimal number concat(8,m) is a square.at n=27A273363
• Triangle read by rows: T(n,k) = 4*T(n-1,k-1) + T(n,k-1) with T(2*m,0) = 0 and T(2*m+1,0) = 5^m.at n=49A292466
• Number of 11-regular partitions of n (no part is a multiple of 11).at n=37A328545
• a(n) is the number of edges formed by n-secting the angles of a pentagon.at n=41A335555
• Dirichlet convolution of A133494 [3^(n-1)] with A349452 (Dirichlet inverse of A011782, 2^(n-1)).at n=9A349567
• Number of subsets of {1,2,...,n} such that no two elements differ by 1, 3, or 4.at n=28A351874
• Numbers k such that the k-th maximal run of composite numbers has length different from all prior maximal runs. Sorted positions of first appearances in A176246 (or A046933 shifted).at n=38A373400