4194284domain: NAppears in sequencesa(n) = 2^(n+1) - n + 1.at n=21A132753If an array is made of columns of -nacci sequences (Fibonacci, tribonacci, etc.), all starting with 1,1,2,..., the NW-to-SE diagonals can be extended by computation. This sequence is diagonal 6. See A159741 for details.at n=17A159742