21855

Appears in sequences

• a(0) = 1, a(n) = 13*n^2 + 2 for n>0.at n=41A010004
• Least k such that 1+2+...+k >= E{1,2,...,n}, where E is the 4th elementary symmetric function.at n=20A027918
• a(n) = (n-1)*(2*n-1)*(3*n-1).at n=16A033594
• Concatenate Fibonacci(n+2), Fibonacci(n) and Fibonacci(n+4).at n=6A134551
• Number of 0..n arrays x(0..4) of 5 elements with each no smaller than the sum of its previous elements modulo (n+1).at n=10A200254
• Number of (n+1) X (2+1) 0..2 arrays with no element unequal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.at n=14A231390
• Triangle read by rows, T(n,k) = Sum_{j=0..n} (-1)^(n-j)*C(-j,-n)*L(j,k), L the unsigned Lah numbers A271703, for n>=0 and 0<=k<=n.at n=31A271704
• Number of partitions of n in which the sequence of the sum of the same summands is increasing.at n=53A304428
• a(0) = a(1) = a(2) = 1; thereafter a(n) = a(n-1) - (-1)^n*a(n-2) + 2*a(n-3).at n=34A329301
• Products k of 4 distinct primes (or tetraprimes) such that k has no squarefree neighbors.at n=32A364141
• Numbers k > 4 such that both k - 2^(2^m) and k + 2^(2^m) are prime for every natural m > 0 with 2^(2^m) < k.at n=20A371303