Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.
1,2
Table of n, a(n) for n=1..5.
Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.
Sequence in context: A074996 A045055 A202418 * A237178 A184227 A203351
Adjacent sequences: A069424 A069425 A069426 * A069428 A069429 A069430
nonn
R. H. Hardin, Mar 22 2002.
approved