80820

Appears in sequences

• a(1) = 1; for n>1, sum of binomial(n,k) as k runs over RRS(n), the reduced residue system of n.at n=17A056188
• Number of (n+2)X(4+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 4 6 or 7.at n=4A252554
• T(n,k) = Number of (n+2) X (k+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 1 2 4 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 1 2 4 6 or 7.at n=32A252558
• Number of (5+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 4 6 or 7.at n=3A252563
• Number of (n,1)-polyominoes.at n=9A286344
• Array read by diagonals downwards: A(n,k) for n>=2 and k>=0 is the number of (n,k)-polyominoes.at n=53A381030