21243

Appears in sequences

• Numbers n such that 81*2^n-1 is prime.at n=20A050566
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (-1, 1, -1), (1, -1, -1), (1, 0, 1)}.at n=10A148541
• Number of nX2 0..4 arrays with values 0..4 introduced in row major order and each element equal to one or two horizontal and vertical neighbors.at n=6A198663
• Number of nX7 0..4 arrays with values 0..4 introduced in row major order and each element equal to one or two horizontal and vertical neighbors.at n=1A198668
• T(n,k) is the number of n X k 0..4 arrays with values 0..4 introduced in row major order and each element equal to one or two horizontal and vertical neighbors.at n=29A198669
• T(n,k) is the number of n X k 0..4 arrays with values 0..4 introduced in row major order and each element equal to one or two horizontal and vertical neighbors.at n=34A198669
• Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any element at a city block distance of two, and containing the value n(n+1)/2-2.at n=19A212031
• a(n) is the least value of k such that the decimal expansion of n^k contains nine consecutive identical digits.at n=2A217164
• Total sum of parts of multiplicity 8 in all partitions of n.at n=42A222736
• Squarefree terms of A276655.at n=26A276756
• Numbers whose Euler totient function is equal to the product of the number of divisors of their k first powers, for some k.at n=41A283759
• Expansion of (-1 + Product_{k>=1} 1 / (1 + (-x)^k))^3.at n=38A341241