81380208

Appears in sequences

• Base 5 digits are, in order, the first n terms of the periodic sequence with initial period 1,3.at n=11A037577
• Number of black-square subarrays of (n+2) X (1+2) 0..3 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero.at n=22A230928
• Number of black-square subarrays of (n+2) X (1+2) 0..3 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero.at n=23A230928
• Number of n X 3 0..3 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero.at n=12A231103
• a(n) = (2*5^n + 3*(-1)^(floor((n-1)/3)) + (-1)^n)/6.at n=12A276508