OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A281871(n+4,n).
EXAMPLE
a(2) = 3: {1,3}, {3,6}, {4,5}.
a(3) = 5: {1,2,6}, {1,3,5}, {2,3,4}, {3,6,7}, {4,5,7}.
a(4) = 8: {1,2,5,8}, {1,2,6,7}, {1,3,4,8}, {1,3,5,7}, {1,4,5,6}, {2,3,4,7}, {2,3,5,6}, {4,6,7,8}.
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 03 2017
STATUS
approved