24021

Appears in sequences

• a(n) = 100*n^2 + 100*n + 21.at n=15A152161
• Numbers whose sum of triangular divisors is also a divisor and greater than 1.at n=32A209311
• Number of nX2 0..3 arrays with no more than floor(nX2/2) elements unequal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..3 order.at n=8A222373
• T(n,k)=Number of nXk 0..3 arrays with no more than floor(nXk/2) elements unequal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..3 order.at n=46A222378
• Numbers k that are equal to the product of the largest triangular proper divisor of k and the sum of all triangular proper divisors of k.at n=2A225881
• a(n) = prime(n)^2 - 4*prime(n).at n=34A245034
• G.f. satisfies: A(x) = Sum_{n>=0} x^n * Sum_{k=0..n} C(n,k) * (A(x)^k - x^k)^k * x^(k*(n-k)).at n=7A245107
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 187", based on the 5-celled von Neumann neighborhood.at n=32A270675
• Largest cost for a permutation problem.at n=41A367185